Documentation

structure IsLinearMap (R : Type u) {M : Type v} {M₂ : Type w} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] (f : M → M₂) :

A map f between modules over a semiring is linear if it satisfies the two properties f (x + y) = f x + f y and f (c • x) = c • f x. The predicate IsLinearMap R f asserts this property. A bundled version is available with LinearMap, and should be favored over IsLinearMap most of the time.

map_add (x y : M) : f (x + y) = f x + f y
A linear map preserves addition.
map_smul (c : R) (x : M) : f (c • x) = c • f x
A linear map preserves scalar multiplication.

Instances For

structure LinearMap {R : Type u_14} {S : Type u_15} [Semiring R] [Semiring S] (σ : R →+* S) (M : Type u_16) (M₂ : Type u_17) [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module S M₂] extends M →ₙ+ M₂, M →ₑ[⇑σ] M₂ :

Type (max u_16 u_17)

A map f between an R-module and an S-module over a ring homomorphism σ : R →+* S is semilinear if it satisfies the two properties f (x + y) = f x + f y and f (c • x) = (σ c) • f x. Elements of LinearMap σ M M₂ (available under the notation M →ₛₗ[σ] M₂) are bundled versions of such maps. For plain linear maps (i.e. for which σ = RingHom.id R), the notation M →ₗ[R] M₂ is available. An unbundled version of plain linear maps is available with the predicate IsLinearMap, but it should be avoided most of the time.

toFun : M → M₂
map_add' (x y : M) : self.toFun (x + y) = self.toFun x + self.toFun y
map_smul' (m : R) (x : M) : self.toFun (m • x) = σ m • self.toFun x

Instances For

def «term_→ₛₗ[_]_» :

M →ₛₗ[σ] N is the type of σ-semilinear maps from M to N.

Equations

Instances For

def «term_→ₗ[_]_» :

M →ₗ[R] N is the type of R-linear maps from M to N.

Equations

Instances For

class SemilinearMapClass (F : Type u_14) {R : outParam (Type u_15)} {S : outParam (Type u_16)} [Semiring R] [Semiring S] (σ : outParam (R →+* S)) (M : outParam (Type u_17)) (M₂ : outParam (Type u_18)) [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module S M₂] [FunLike F M M₂] extends AddHomClass F M M₂, MulActionSemiHomClass F (⇑σ) M M₂ :

SemilinearMapClass F σ M M₂ asserts F is a type of bundled σ-semilinear maps M → M₂.

See also LinearMapClass F R M M₂ for the case where σ is the identity map on R.

A map f between an R-module and an S-module over a ring homomorphism σ : R →+* S is semilinear if it satisfies the two properties f (x + y) = f x + f y and f (c • x) = (σ c) • f x.

map_add (f : F) (x y : M) : f (x + y) = f x + f y
map_smulₛₗ (f : F) (c : R) (x : M) : f (c • x) = σ c • f x

Instances

@[reducible, inline]

abbrev LinearMapClass (F : Type u_14) (R : outParam (Type u_15)) (M : Type u_16) (M₂ : Type u_17) [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [FunLike F M M₂] :

LinearMapClass F R M M₂ asserts F is a type of bundled R-linear maps M → M₂.

This is an abbreviation for SemilinearMapClass F (RingHom.id R) M M₂.

Equations

Instances For

theorem LinearMapClass.map_smul {R : outParam (Type u_14)} {M : outParam (Type u_15)} {M₂ : outParam (Type u_16)} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] {F : Type u_17} [FunLike F M M₂] [LinearMapClass F R M M₂] (f : F) (r : R) (x : M) :

f (r • x) = r • f x

@[instance 100]

instance SemilinearMapClass.instAddMonoidHomClass {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} (F : Type u_14) [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} [FunLike F M M₃] [SemilinearMapClass F σ M M₃] :

AddMonoidHomClass F M M₃

@[instance 100]

instance SemilinearMapClass.distribMulActionSemiHomClass {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} (F : Type u_14) [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} [FunLike F M M₃] [SemilinearMapClass F σ M M₃] :

DistribMulActionSemiHomClass F (⇑σ) M M₃

theorem SemilinearMapClass.map_smul_inv {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} {F : Type u_14} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : F) [FunLike F M M₃] [SemilinearMapClass F σ M M₃] {σ' : S →+* R} [RingHomInvPair σ σ'] (c : S) (x : M) :

c • f x = f (σ' c • x)

def SemilinearMapClass.semilinearMap {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} {F : Type u_14} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : F) [FunLike F M M₃] [SemilinearMapClass F σ M M₃] :

M →ₛₗ[σ] M₃

Reinterpret an element of a type of semilinear maps as a semilinear map.

Equations

Instances For

instance SemilinearMapClass.instCoeToSemilinearMap {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} {F : Type u_14} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} [FunLike F M M₃] [SemilinearMapClass F σ M M₃] :

CoeHead F (M →ₛₗ[σ] M₃)

Reinterpret an element of a type of semilinear maps as a semilinear map.

Equations

@[reducible, inline]

abbrev LinearMapClass.linearMap {R : Type u_1} {M₁ : Type u_9} {M₂ : Type u_10} {F : Type u_14} [Semiring R] [AddCommMonoid M₁] [AddCommMonoid M₂] [Module R M₁] [Module R M₂] (f : F) [FunLike F M₁ M₂] [LinearMapClass F R M₁ M₂] :

M₁ →ₗ[R] M₂

Reinterpret an element of a type of linear maps as a linear map.

Equations

Instances For

instance LinearMapClass.instCoeToLinearMap {R : Type u_1} {M₁ : Type u_9} {M₂ : Type u_10} {F : Type u_14} [Semiring R] [AddCommMonoid M₁] [AddCommMonoid M₂] [Module R M₁] [Module R M₂] [FunLike F M₁ M₂] [LinearMapClass F R M₁ M₂] :

CoeHead F (M₁ →ₗ[R] M₂)

Reinterpret an element of a type of linear maps as a linear map.

Equations

instance LinearMap.instFunLike {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} :

FunLike (M →ₛₗ[σ] M₃) M M₃

Equations

instance LinearMap.semilinearMapClass {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} :

SemilinearMapClass (M →ₛₗ[σ] M₃) σ M M₃

@[simp]

theorem LinearMap.coe_coe {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {F : Type u_14} [FunLike F M M₃] [SemilinearMapClass F σ M M₃] {f : F} :

⇑↑f = ⇑f

def LinearMap.toDistribMulActionHom {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) :

M →ₑ+[↑σ] M₃

The DistribMulActionHom underlying a LinearMap.

Equations

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@[simp]

theorem LinearMap.coe_toAddHom {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) :

⇑f.toAddHom = ⇑f

theorem LinearMap.toFun_eq_coe {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {f : M →ₛₗ[σ] M₃} :

f.toFun = ⇑f

theorem LinearMap.ext {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {f g : M →ₛₗ[σ] M₃} (h : ∀ (x : M), f x = g x) :

f = g

theorem LinearMap.ext_iff {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {f g : M →ₛₗ[σ] M₃} :

f = g ↔ ∀ (x : M), f x = g x

def LinearMap.copy {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (f' : M → M₃) (h : f' = ⇑f) :

M →ₛₗ[σ] M₃

Copy of a LinearMap with a new toFun equal to the old one. Useful to fix definitional equalities.

Equations

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@[simp]

theorem LinearMap.coe_copy {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (f' : M → M₃) (h : f' = ⇑f) :

⇑(f.copy f' h) = f'

theorem LinearMap.copy_eq {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (f' : M → M₃) (h : f' = ⇑f) :

f.copy f' h = f

@[simp]

theorem LinearMap.coe_mk {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₙ+ M₃) (h : ∀ (m : R) (x : M), f.toFun (m • x) = σ m • f.toFun x) :

⇑{ toAddHom := f, map_smul' := h } = ⇑f

@[simp]

theorem LinearMap.coe_addHom_mk {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₙ+ M₃) (h : ∀ (m : R) (x : M), f.toFun (m • x) = σ m • f.toFun x) :

↑{ toAddHom := f, map_smul' := h } = f

theorem LinearMap.coe_semilinearMap {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {F : Type u_14} [FunLike F M M₃] [SemilinearMapClass F σ M M₃] (f : F) :

⇑↑f = ⇑f

theorem LinearMap.toLinearMap_injective {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {F : Type u_14} [FunLike F M M₃] [SemilinearMapClass F σ M M₃] {f g : F} (h : ↑f = ↑g) :

f = g

def LinearMap.id {R : Type u_1} {M : Type u_8} [Semiring R] [AddCommMonoid M] [Module R M] :

M →ₗ[R] M

Identity map as a LinearMap

Equations

Instances For

theorem LinearMap.id_apply {R : Type u_1} {M : Type u_8} [Semiring R] [AddCommMonoid M] [Module R M] (x : M) :

id x = x

@[simp]

theorem LinearMap.id_coe {R : Type u_1} {M : Type u_8} [Semiring R] [AddCommMonoid M] [Module R M] :

⇑id = _root_.id

def LinearMap.id' {R : Type u_1} {M : Type u_8} [Semiring R] [AddCommMonoid M] [Module R M] {σ : R →+* R} [RingHomId σ] :

M →ₛₗ[σ] M

A generalisation of LinearMap.id that constructs the identity function as a σ-semilinear map for any ring homomorphism σ which we know is the identity.

Equations

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@[simp]

theorem LinearMap.id'_apply {R : Type u_1} {M : Type u_8} [Semiring R] [AddCommMonoid M] [Module R M] {σ : R →+* R} [RingHomId σ] (x : M) :

id' x = x

@[simp]

theorem LinearMap.id'_coe {R : Type u_1} {M : Type u_8} [Semiring R] [AddCommMonoid M] [Module R M] {σ : R →+* R} [RingHomId σ] :

⇑id' = _root_.id

theorem LinearMap.isLinear {R : Type u_1} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] (fₗ : M →ₗ[R] M₂) :

IsLinearMap R ⇑fₗ

Function.Injective DFunLike.coe

theorem LinearMap.coe_injective {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} :

theorem LinearMap.congr_arg {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {f : M →ₛₗ[σ] M₃} {x x' : M} :

x = x' → f x = f x'

theorem LinearMap.congr_fun {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} {f g : M →ₛₗ[σ] M₃} (h : f = g) (x : M) :

f x = g x

If two linear maps are equal, they are equal at each point.

@[simp]

theorem LinearMap.mk_coe {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (h : ∀ (m : R) (x : M), (↑f).toFun (m • x) = σ m • (↑f).toFun x) :

{ toAddHom := ↑f, map_smul' := h } = f

@[simp]

theorem LinearMap.mk_coe' {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (h : ∀ (m : R) (x : M), f.toFun (m • x) = σ m • f.toFun x) :

{ toAddHom := f.toAddHom, map_smul' := h } = f

theorem LinearMap.map_add {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (x y : M) :

f (x + y) = f x + f y

theorem LinearMap.map_zero {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) :

f 0 = 0

@[simp]

theorem LinearMap.map_smulₛₗ {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (c : R) (x : M) :

f (c • x) = σ c • f x

theorem LinearMap.map_smul {R : Type u_1} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] (fₗ : M →ₗ[R] M₂) (c : R) (x : M) :

fₗ (c • x) = c • fₗ x

theorem LinearMap.map_smul_inv {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) {σ' : S →+* R} [RingHomInvPair σ σ'] (c : S) (x : M) :

c • f x = f (σ' c • x)

@[simp]

theorem LinearMap.map_eq_zero_iff {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) (h : Function.Injective ⇑f) {x : M} :

f x = 0 ↔ x = 0

class LinearMap.CompatibleSMul (M : Type u_8) (M₂ : Type u_10) [AddCommMonoid M] [AddCommMonoid M₂] (R : Type u_14) (S : Type u_15) [Semiring S] [SMul R M] [Module S M] [SMul R M₂] [Module S M₂] :

A typeclass for SMul structures which can be moved through a LinearMap. This typeclass is generated automatically from an IsScalarTower instance, but exists so that we can also add an instance for AddCommGroup.toIntModule, allowing z • to be moved even if S does not support negation.

map_smul (fₗ : M →ₗ[S] M₂) (c : R) (x : M) : fₗ (c • x) = c • fₗ x
Scalar multiplication by R of M can be moved through linear maps.

Instances

@[instance 100]

instance LinearMap.IsScalarTower.compatibleSMul {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] {R : Type u_14} {S : Type u_15} [Semiring S] [SMul R M] [Module S M] [SMul R M₂] [Module S M₂] [SMul R S] [IsScalarTower R S M] [IsScalarTower R S M₂] :

CompatibleSMul M M₂ R S

instance LinearMap.IsScalarTower.compatibleSMul' {M : Type u_8} [AddCommMonoid M] {R : Type u_14} {S : Type u_15} [Semiring S] [SMul R M] [Module S M] [SMul R S] [IsScalarTower R S M] :

CompatibleSMul S M R S

@[simp]

theorem LinearMap.map_smul_of_tower {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] {R : Type u_14} {S : Type u_15} [Semiring S] [SMul R M] [Module S M] [SMul R M₂] [Module S M₂] [CompatibleSMul M M₂ R S] (fₗ : M →ₗ[S] M₂) (c : R) (x : M) :

fₗ (c • x) = c • fₗ x

theorem LinearMapClass.map_smul_of_tower {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] {R : Type u_14} {S : Type u_15} [Semiring S] [SMul R M] [Module S M] [SMul R M₂] [Module S M₂] {F : Type u_16} [LinearMap.CompatibleSMul M M₂ R S] [FunLike F M M₂] [LinearMapClass F S M M₂] (fₗ : F) (c : R) (x : M) :

fₗ (c • x) = c • fₗ x

theorem LinearMap.isScalarTower_of_injective {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] (R : Type u_14) {S : Type u_15} [Semiring S] [SMul R M] [Module S M] [SMul R M₂] [Module S M₂] [SMul R S] [CompatibleSMul M M₂ R S] [IsScalarTower R S M₂] (f : M →ₗ[S] M₂) (hf : Function.Injective ⇑f) :

IsScalarTower R S M

@[simp]

theorem map_zsmul_unit {F : Type u_16} {M : Type u_17} {N : Type u_18} [AddGroup M] [AddGroup N] [FunLike F M N] [AddMonoidHomClass F M N] (f : F) (c : ℤ ˣ) (m : M) :

f (c • m) = c • f m

theorem LinearMap.isLinearMap_of_compatibleSMul (R : Type u_1) {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] (f : M →ₗ[S] M₂) :

IsLinearMap R ⇑f

def LinearMap.toAddMonoidHom {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) :

M →+ M₃

convert a linear map to an additive map

Equations

Instances For

@[simp]

theorem LinearMap.toAddMonoidHom_coe {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} (f : M →ₛₗ[σ] M₃) :

⇑f.toAddMonoidHom = ⇑f

def LinearMap.restrictScalars (R : Type u_1) {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] (fₗ : M →ₗ[S] M₂) :

M →ₗ[R] M₂

If M and M₂ are both R-modules and S-modules and R-module structures are defined by an action of R on S (formally, we have two scalar towers), then any S-linear map from M to M₂ is R-linear.

See also LinearMap.map_smul_of_tower.

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instance LinearMap.coeIsScalarTower (R : Type u_1) {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] :

CoeHTCT (M →ₗ[S] M₂) (M →ₗ[R] M₂)

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@[simp]

theorem LinearMap.coe_restrictScalars (R : Type u_1) {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] (f : M →ₗ[S] M₂) :

⇑(↑R f) = ⇑f

theorem LinearMap.restrictScalars_apply (R : Type u_1) {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] (fₗ : M →ₗ[S] M₂) (x : M) :

(↑R fₗ) x = fₗ x

theorem LinearMap.restrictScalars_injective (R : Type u_1) {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] :

Function.Injective ↑R

@[simp]

theorem LinearMap.restrictScalars_inj (R : Type u_1) {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] (fₗ gₗ : M →ₗ[S] M₂) :

↑R fₗ = ↑R gₗ ↔ fₗ = gₗ

Function.Injective toAddMonoidHom

theorem LinearMap.toAddMonoidHom_injective {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₃] [Module R M] [Module S M₃] {σ : R →+* S} :

theorem LinearMap.ext_ring {R : Type u_1} {S : Type u_5} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M₃] [Module S M₃] {σ : R →+* S} {f g : R →ₛₗ[σ] M₃} (h : f 1 = g 1) :

f = g

If two σ-linear maps from R are equal on 1, then they are equal.

theorem LinearMap.ext_ring_iff {R : Type u_1} {S : Type u_5} {M₃ : Type u_11} [Semiring R] [Semiring S] [AddCommMonoid M₃] [Module S M₃] {σ : R →+* S} {f g : R →ₛₗ[σ] M₃} :

f = g ↔ f 1 = g 1

def RingHom.toSemilinearMap {R : Type u_1} {S : Type u_5} [Semiring R] [Semiring S] (f : R →+* S) :

R →ₛₗ[f] S

Interpret a RingHom f as an f-semilinear map.

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@[simp]

theorem RingHom.toSemilinearMap_apply {R : Type u_1} {S : Type u_5} [Semiring R] [Semiring S] (f : R →+* S) (a✝ : R) :

f.toSemilinearMap a✝ = (↑↑f).toFun a✝

@[simp]

theorem RingHom.coe_toSemilinearMap {R : Type u_1} {S : Type u_5} [Semiring R] [Semiring S] (f : R →+* S) :

⇑f.toSemilinearMap = ⇑f

def LinearMap.comp {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M₂ →ₛₗ[σ₂₃] M₃) (g : M₁ →ₛₗ[σ₁₂] M₂) :

M₁ →ₛₗ[σ₁₃] M₃

Composition of two linear maps is a linear map

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def LinearMap.compNotation :

∘ₗ is notation for composition of two linear (not semilinear!) maps into a linear map. This is useful when Lean is struggling to infer the RingHomCompTriple instance.

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Lean.PrettyPrinter.Delaborator.Delab

def LinearMap.compNotation.«delab_app.LinearMap.comp» :

Pretty printer defined by notation3 command.

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def LinearMap.«term_∘ₛₗ_» :

Composition of two linear maps is a linear map

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theorem LinearMap.comp_apply {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M₂ →ₛₗ[σ₂₃] M₃) (g : M₁ →ₛₗ[σ₁₂] M₂) (x : M₁) :

(f ∘ₛₗ g) x = f (g x)

@[simp]

theorem LinearMap.coe_comp {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M₂ →ₛₗ[σ₂₃] M₃) (g : M₁ →ₛₗ[σ₁₂] M₂) :

⇑(f ∘ₛₗ g) = ⇑f ∘ ⇑g

@[simp]

theorem LinearMap.comp_id {R₂ : Type u_3} {R₃ : Type u_4} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₂] [Semiring R₃] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₂₃ : R₂ →+* R₃} (f : M₂ →ₛₗ[σ₂₃] M₃) :

f ∘ₛₗ id = f

@[simp]

theorem LinearMap.id_comp {R₂ : Type u_3} {R₃ : Type u_4} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₂] [Semiring R₃] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₂₃ : R₂ →+* R₃} (f : M₂ →ₛₗ[σ₂₃] M₃) :

id ∘ₛₗ f = f

theorem LinearMap.comp_assoc {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] {R₄ : Type u_14} {M₄ : Type u_15} [Semiring R₄] [AddCommMonoid M₄] [Module R₄ M₄] {σ₃₄ : R₃ →+* R₄} {σ₂₄ : R₂ →+* R₄} {σ₁₄ : R₁ →+* R₄} [RingHomCompTriple σ₂₃ σ₃₄ σ₂₄] [RingHomCompTriple σ₁₃ σ₃₄ σ₁₄] [RingHomCompTriple σ₁₂ σ₂₄ σ₁₄] (f : M₁ →ₛₗ[σ₁₂] M₂) (g : M₂ →ₛₗ[σ₂₃] M₃) (h : M₃ →ₛₗ[σ₃₄] M₄) :

(h ∘ₛₗ g) ∘ₛₗ f = h ∘ₛₗ g ∘ₛₗ f

theorem Function.Surjective.injective_linearMapComp_right {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] {g : M₁ →ₛₗ[σ₁₂] M₂} (hg : Surjective ⇑g) :

Injective fun (f : M₂ →ₛₗ[σ₂₃] M₃) => f ∘ₛₗ g

The linear map version of Function.Surjective.injective_comp_right

@[simp]

theorem LinearMap.cancel_right {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] {f : M₂ →ₛₗ[σ₂₃] M₃} {g : M₁ →ₛₗ[σ₁₂] M₂} {f' : M₂ →ₛₗ[σ₂₃] M₃} (hg : Function.Surjective ⇑g) :

f ∘ₛₗ g = f' ∘ₛₗ g ↔ f = f'

theorem Function.Injective.injective_linearMapComp_left {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] {f : M₂ →ₛₗ[σ₂₃] M₃} (hf : Injective ⇑f) :

Injective fun (g : M₁ →ₛₗ[σ₁₂] M₂) => f ∘ₛₗ g

The linear map version of Function.Injective.comp_left

theorem LinearMap.surjective_comp_left_of_exists_rightInverse {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] {f : M₂ →ₛₗ[σ₂₃] M₃} {σ₃₂ : R₃ →+* R₂} [RingHomInvPair σ₂₃ σ₃₂] [RingHomCompTriple σ₁₃ σ₃₂ σ₁₂] (hf : ∃ (f' : M₃ →ₛₗ[σ₃₂] M₂), f ∘ₛₗ f' = id) :

Function.Surjective fun (g : M₁ →ₛₗ[σ₁₂] M₂) => f ∘ₛₗ g

@[simp]

theorem LinearMap.cancel_left {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M₁ : Type u_9} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M₁] [AddCommMonoid M₂] [AddCommMonoid M₃] {module_M₁ : Module R₁ M₁} {module_M₂ : Module R₂ M₂} {module_M₃ : Module R₃ M₃} {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] {f : M₂ →ₛₗ[σ₂₃] M₃} {g g' : M₁ →ₛₗ[σ₁₂] M₂} (hf : Function.Injective ⇑f) :

f ∘ₛₗ g = f ∘ₛₗ g' ↔ g = g'

def LinearMap.inverse {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module S M₂] {σ : R →+* S} {σ' : S →+* R} [RingHomInvPair σ σ'] (f : M →ₛₗ[σ] M₂) (g : M₂ → M) (h₁ : Function.LeftInverse g ⇑f) (h₂ : Function.RightInverse g ⇑f) :

M₂ →ₛₗ[σ'] M

If a function g is a left and right inverse of a linear map f, then g is linear itself.

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theorem LinearMap.injective_of_comp_eq_id {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module S M₂] {σ : R →+* S} {σ' : S →+* R} [RingHomInvPair σ σ'] (f : M →ₛₗ[σ] M₂) (g : M₂ →ₛₗ[σ'] M) (h : g ∘ₛₗ f = id) :

Function.Injective ⇑f

theorem LinearMap.surjective_of_comp_eq_id {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module S M₂] {σ : R →+* S} {σ' : S →+* R} [RingHomInvPair σ σ'] (f : M →ₛₗ[σ] M₂) (g : M₂ →ₛₗ[σ'] M) (h : g ∘ₛₗ f = id) :

Function.Surjective ⇑g

theorem LinearMap.map_neg {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommGroup M] [AddCommGroup M₂] {module_M : Module R M} {module_M₂ : Module S M₂} {σ : R →+* S} (f : M →ₛₗ[σ] M₂) (x : M) :

f (-x) = -f x

theorem LinearMap.map_sub {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring S] [AddCommGroup M] [AddCommGroup M₂] {module_M : Module R M} {module_M₂ : Module S M₂} {σ : R →+* S} (f : M →ₛₗ[σ] M₂) (x y : M) :

f (x - y) = f x - f y

instance LinearMap.CompatibleSMul.intModule {M : Type u_8} {M₂ : Type u_10} [AddCommGroup M] [AddCommGroup M₂] {S : Type u_14} [Semiring S] [Module S M] [Module S M₂] :

CompatibleSMul M M₂ ℤ S

instance LinearMap.CompatibleSMul.units {M : Type u_8} {M₂ : Type u_10} [AddCommGroup M] [AddCommGroup M₂] {R : Type u_14} {S : Type u_15} [Monoid R] [MulAction R M] [MulAction R M₂] [Semiring S] [Module S M] [Module S M₂] [CompatibleSMul M M₂ R S] :

CompatibleSMul M M₂ Rˣ S

def Module.compHom.toLinearMap {R : Type u_14} {S : Type u_15} [Semiring R] [Semiring S] (g : R →+* S) :

R →ₗ[R] S

g : R →+* S is R-linear when the module structure on S is Module.compHom S g .

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@[simp]

theorem Module.compHom.toLinearMap_apply {R : Type u_14} {S : Type u_15} [Semiring R] [Semiring S] (g : R →+* S) (a : R) :

(toLinearMap g) a = g a

@[deprecated "No deprecation message was provided." (since := "2024-11-08")]

def DistribMulActionHom.toSemilinearMap {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] [Semiring R] [Module R M] [Semiring S] [Module S M₂] {σ : R →+* S} (fₗ : M →ₑ+[↑σ] M₂) :

M →ₛₗ[σ] M₂

A DistribMulActionHom between two modules is a linear map.

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instance DistribMulActionHom.instSemilinearMapClass {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] [Semiring R] [Module R M] [Semiring S] [Module S M₂] {σ : R →+* S} :

SemilinearMapClass (M →ₑ+[↑σ] M₂) σ M M₂

@[deprecated "No deprecation message was provided." (since := "2024-11-08")]

def DistribMulActionHom.toLinearMap {R : Type u_1} {M : Type u_8} {M₃ : Type u_11} [AddCommMonoid M] [AddCommMonoid M₃] [Semiring R] [Module R M] [Module R M₃] (fₗ : M →+[R] M₃) :

M →ₗ[R] M₃

A DistribMulActionHom between two modules is a linear map.

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instance DistribMulActionHom.instLinearMapClassId {R : Type u_1} {M : Type u_8} {M₃ : Type u_11} [AddCommMonoid M] [AddCommMonoid M₃] [Semiring R] [Module R M] [Module R M₃] :

LinearMapClass (M →+[R] M₃) R M M₃

A DistribMulActionHom between two modules is a linear map.

@[simp]

theorem DistribMulActionHom.coe_toLinearMap {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] [Semiring R] [Module R M] [Semiring S] [Module S M₂] {σ : R →+* S} (f : M →ₑ+[↑σ] M₂) :

⇑↑f = ⇑f

theorem DistribMulActionHom.toLinearMap_injective {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] [Semiring R] [Module R M] [Semiring S] [Module S M₂] {σ : R →+* S} {f g : M →ₑ+[↑σ] M₂} (h : ↑f = ↑g) :

f = g

def IsLinearMap.mk' {R : Type u_1} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] (f : M → M₂) (lin : IsLinearMap R f) :

M →ₗ[R] M₂

Convert an IsLinearMap predicate to a LinearMap

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@[simp]

theorem IsLinearMap.mk'_apply {R : Type u_1} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] {f : M → M₂} (lin : IsLinearMap R f) (x : M) :

(mk' f lin) x = f x

theorem IsLinearMap.isLinearMap_smul {R : Type u_14} {M : Type u_15} [CommSemiring R] [AddCommMonoid M] [Module R M] (c : R) :

IsLinearMap R fun (z : M) => c • z

theorem IsLinearMap.isLinearMap_smul' {R : Type u_14} {M : Type u_15} [Semiring R] [AddCommMonoid M] [Module R M] (a : M) :

IsLinearMap R fun (c : R) => c • a

theorem IsLinearMap.map_zero {R : Type u_1} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R M₂] {f : M → M₂} (lin : IsLinearMap R f) :

f 0 = 0

theorem IsLinearMap.isLinearMap_neg {R : Type u_1} {M : Type u_8} [Semiring R] [AddCommGroup M] [Module R M] :

IsLinearMap R fun (z : M) => -z

theorem IsLinearMap.map_neg {R : Type u_1} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [AddCommGroup M] [AddCommGroup M₂] [Module R M] [Module R M₂] {f : M → M₂} (lin : IsLinearMap R f) (x : M) :

f (-x) = -f x

theorem IsLinearMap.map_sub {R : Type u_1} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [AddCommGroup M] [AddCommGroup M₂] [Module R M] [Module R M₂] {f : M → M₂} (lin : IsLinearMap R f) (x y : M) :

f (x - y) = f x - f y

def AddMonoidHom.toNatLinearMap {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] (f : M →+ M₂) :

M →ₗ[ℕ ] M₂

Reinterpret an additive homomorphism as an ℕ-linear map.

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Instances For

Function.Injective toNatLinearMap

theorem AddMonoidHom.toNatLinearMap_injective {M : Type u_8} {M₂ : Type u_10} [AddCommMonoid M] [AddCommMonoid M₂] :

def AddMonoidHom.toIntLinearMap {M : Type u_8} {M₂ : Type u_10} [AddCommGroup M] [AddCommGroup M₂] (f : M →+ M₂) :

M →ₗ[ℤ ] M₂

Reinterpret an additive homomorphism as a ℤ-linear map.

Equations

Instances For

Function.Injective toIntLinearMap

theorem AddMonoidHom.toIntLinearMap_injective {M : Type u_8} {M₂ : Type u_10} [AddCommGroup M] [AddCommGroup M₂] :

@[simp]

theorem AddMonoidHom.coe_toIntLinearMap {M : Type u_8} {M₂ : Type u_10} [AddCommGroup M] [AddCommGroup M₂] (f : M →+ M₂) :

⇑f.toIntLinearMap = ⇑f

instance LinearMap.instSMul {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Monoid S] [DistribMulAction S M₂] [SMulCommClass R₂ S M₂] :

SMul S (M →ₛₗ[σ₁₂] M₂)

Equations

@[simp]

theorem LinearMap.smul_apply {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Monoid S] [DistribMulAction S M₂] [SMulCommClass R₂ S M₂] (a : S) (f : M →ₛₗ[σ₁₂] M₂) (x : M) :

(a • f) x = a • f x

theorem LinearMap.coe_smul {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Monoid S] [DistribMulAction S M₂] [SMulCommClass R₂ S M₂] (a : S) (f : M →ₛₗ[σ₁₂] M₂) :

⇑(a • f) = a • ⇑f

instance LinearMap.instSMulCommClass {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {T : Type u_7} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Monoid S] [DistribMulAction S M₂] [SMulCommClass R₂ S M₂] [Monoid T] [DistribMulAction T M₂] [SMulCommClass R₂ T M₂] [SMulCommClass S T M₂] :

SMulCommClass S T (M →ₛₗ[σ₁₂] M₂)

instance LinearMap.instIsScalarTower {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {T : Type u_7} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Monoid S] [DistribMulAction S M₂] [SMulCommClass R₂ S M₂] [Monoid T] [DistribMulAction T M₂] [SMulCommClass R₂ T M₂] [SMul S T] [IsScalarTower S T M₂] :

IsScalarTower S T (M →ₛₗ[σ₁₂] M₂)

instance LinearMap.instIsCentralScalar {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Monoid S] [DistribMulAction S M₂] [SMulCommClass R₂ S M₂] [DistribMulAction Sᵐᵒᵖ M₂] [SMulCommClass R₂ Sᵐᵒᵖ M₂] [IsCentralScalar S M₂] :

IsCentralScalar S (M →ₛₗ[σ₁₂] M₂)

Arithmetic on the codomain #

instance LinearMap.instZero {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} :

Zero (M →ₛₗ[σ₁₂] M₂)

The constant 0 map is linear.

Equations

@[simp]

theorem LinearMap.zero_apply {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} (x : M) :

0 x = 0

@[simp]

theorem LinearMap.comp_zero {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommMonoid M₃] [Module R₁ M] [Module R₂ M₂] [Module R₃ M₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (g : M₂ →ₛₗ[σ₂₃] M₃) :

g ∘ₛₗ 0 = 0

@[simp]

theorem LinearMap.zero_comp {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommMonoid M₃] [Module R₁ M] [Module R₂ M₂] [Module R₃ M₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M →ₛₗ[σ₁₂] M₂) :

0 ∘ₛₗ f = 0

instance LinearMap.instInhabited {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} :

Inhabited (M →ₛₗ[σ₁₂] M₂)

Equations

@[simp]

theorem LinearMap.default_def {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} :

default = 0

instance LinearMap.uniqueOfLeft {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} [Subsingleton M] :

Unique (M →ₛₗ[σ₁₂] M₂)

Equations

instance LinearMap.uniqueOfRight {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} [Subsingleton M₂] :

Unique (M →ₛₗ[σ₁₂] M₂)

Equations

theorem LinearMap.ne_zero_of_injective {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} [Nontrivial M] {f : M →ₛₗ[σ₁₂] M₂} (hf : Function.Injective ⇑f) :

f ≠ 0

theorem LinearMap.ne_zero_of_surjective {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} [Nontrivial M₂] {f : M →ₛₗ[σ₁₂] M₂} (hf : Function.Surjective ⇑f) :

f ≠ 0

instance LinearMap.instAdd {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} :

Add (M →ₛₗ[σ₁₂] M₂)

The sum of two linear maps is linear.

Equations

@[simp]

theorem LinearMap.add_apply {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} (f g : M →ₛₗ[σ₁₂] M₂) (x : M) :

(f + g) x = f x + g x

theorem LinearMap.add_comp {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommMonoid M₃] [Module R₁ M] [Module R₂ M₂] [Module R₃ M₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M →ₛₗ[σ₁₂] M₂) (g h : M₂ →ₛₗ[σ₂₃] M₃) :

(h + g) ∘ₛₗ f = h ∘ₛₗ f + g ∘ₛₗ f

theorem LinearMap.comp_add {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommMonoid M₃] [Module R₁ M] [Module R₂ M₂] [Module R₃ M₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f g : M →ₛₗ[σ₁₂] M₂) (h : M₂ →ₛₗ[σ₂₃] M₃) :

h ∘ₛₗ (f + g) = h ∘ₛₗ f + h ∘ₛₗ g

instance LinearMap.addCommMonoid {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} :

AddCommMonoid (M →ₛₗ[σ₁₂] M₂)

The type of linear maps is an additive monoid.

Equations

instance LinearMap.instNeg {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {N₂ : Type u_12} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommGroup N₂] [Module R₁ M] [Module R₂ N₂] {σ₁₂ : R₁ →+* R₂} :

Neg (M →ₛₗ[σ₁₂] N₂)

The negation of a linear map is linear.

Equations

@[simp]

theorem LinearMap.neg_apply {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {N₂ : Type u_12} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommGroup N₂] [Module R₁ M] [Module R₂ N₂] {σ₁₂ : R₁ →+* R₂} (f : M →ₛₗ[σ₁₂] N₂) (x : M) :

(-f) x = -f x

@[simp]

theorem LinearMap.neg_comp {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {M₂ : Type u_10} {N₃ : Type u_13} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommGroup N₃] [Module R₁ M] [Module R₂ M₂] [Module R₃ N₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M →ₛₗ[σ₁₂] M₂) (g : M₂ →ₛₗ[σ₂₃] N₃) :

(-g) ∘ₛₗ f = -g ∘ₛₗ f

@[simp]

theorem LinearMap.comp_neg {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {N₂ : Type u_12} {N₃ : Type u_13} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommGroup N₂] [AddCommGroup N₃] [Module R₁ M] [Module R₂ N₂] [Module R₃ N₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M →ₛₗ[σ₁₂] N₂) (g : N₂ →ₛₗ[σ₂₃] N₃) :

g ∘ₛₗ (-f) = -g ∘ₛₗ f

instance LinearMap.instSub {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {N₂ : Type u_12} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommGroup N₂] [Module R₁ M] [Module R₂ N₂] {σ₁₂ : R₁ →+* R₂} :

Sub (M →ₛₗ[σ₁₂] N₂)

The subtraction of two linear maps is linear.

Equations

@[simp]

theorem LinearMap.sub_apply {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {N₂ : Type u_12} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommGroup N₂] [Module R₁ M] [Module R₂ N₂] {σ₁₂ : R₁ →+* R₂} (f g : M →ₛₗ[σ₁₂] N₂) (x : M) :

(f - g) x = f x - g x

theorem LinearMap.sub_comp {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {M₂ : Type u_10} {N₃ : Type u_13} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommGroup N₃] [Module R₁ M] [Module R₂ M₂] [Module R₃ N₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f : M →ₛₗ[σ₁₂] M₂) (g h : M₂ →ₛₗ[σ₂₃] N₃) :

(g - h) ∘ₛₗ f = g ∘ₛₗ f - h ∘ₛₗ f

theorem LinearMap.comp_sub {R₁ : Type u_2} {R₂ : Type u_3} {R₃ : Type u_4} {M : Type u_8} {N₂ : Type u_12} {N₃ : Type u_13} [Semiring R₁] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommGroup N₂] [AddCommGroup N₃] [Module R₁ M] [Module R₂ N₂] [Module R₃ N₃] {σ₁₂ : R₁ →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R₁ →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] (f g : M →ₛₗ[σ₁₂] N₂) (h : N₂ →ₛₗ[σ₂₃] N₃) :

h ∘ₛₗ (g - f) = h ∘ₛₗ g - h ∘ₛₗ f

instance LinearMap.addCommGroup {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {N₂ : Type u_12} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommGroup N₂] [Module R₁ M] [Module R₂ N₂] {σ₁₂ : R₁ →+* R₂} :

AddCommGroup (M →ₛₗ[σ₁₂] N₂)

The type of linear maps is an additive group.

Equations

def LinearMap.evalAddMonoidHom {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} (a : M) :

(M →ₛₗ[σ₁₂] M₂) →+ M₂

Evaluation of a σ₁₂-linear map at a fixed a, as an AddMonoidHom.

Equations

Instances For

@[simp]

theorem LinearMap.evalAddMonoidHom_apply {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} (a : M) (f : M →ₛₗ[σ₁₂] M₂) :

(evalAddMonoidHom a) f = f a

def LinearMap.toAddMonoidHom' {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} :

(M →ₛₗ[σ₁₂] M₂) →+ M →+ M₂

LinearMap.toAddMonoidHom promoted to an AddMonoidHom.

Equations

Instances For

@[simp]

theorem LinearMap.toAddMonoidHom'_apply {R₁ : Type u_2} {R₂ : Type u_3} {M : Type u_8} {M₂ : Type u_10} [Semiring R₁] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R₁ M] [Module R₂ M₂] {σ₁₂ : R₁ →+* R₂} (f : M →ₛₗ[σ₁₂] M₂) :

toAddMonoidHom' f = f.toAddMonoidHom

@[simp]

theorem LinearMap.identityMapOfZeroModuleIsZero {R₁ : Type u_2} {M : Type u_8} [Semiring R₁] [AddCommMonoid M] [Module R₁ M] [Subsingleton M] :

id = 0

If M is the zero module, then the identity map of M is the zero map.

instance LinearMap.instDistribMulAction {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Monoid S] [DistribMulAction S M₂] [SMulCommClass R₂ S M₂] :

DistribMulAction S (M →ₛₗ[σ₁₂] M₂)

Equations

theorem LinearMap.smul_comp {R : Type u_1} {R₂ : Type u_3} {R₃ : Type u_4} {S₃ : Type u_6} {M : Type u_8} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R] [Semiring R₂] [Semiring R₃] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommMonoid M₃] [Module R M] [Module R₂ M₂] [Module R₃ M₃] {σ₁₂ : R →+* R₂} {σ₂₃ : R₂ →+* R₃} {σ₁₃ : R →+* R₃} [RingHomCompTriple σ₁₂ σ₂₃ σ₁₃] [Monoid S₃] [DistribMulAction S₃ M₃] [SMulCommClass R₃ S₃ M₃] (a : S₃) (g : M₂ →ₛₗ[σ₂₃] M₃) (f : M →ₛₗ[σ₁₂] M₂) :

(a • g) ∘ₛₗ f = a • g ∘ₛₗ f

theorem LinearMap.comp_smul {R : Type u_1} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} {M₃ : Type u_11} [Semiring R] [AddCommMonoid M] [AddCommMonoid M₂] [AddCommMonoid M₃] [Module R M] [Monoid S] [DistribMulAction S M₂] [Module R M₂] [Module R M₃] [SMulCommClass R S M₂] [DistribMulAction S M₃] [SMulCommClass R S M₃] [CompatibleSMul M₃ M₂ S R] (g : M₃ →ₗ[R] M₂) (a : S) (f : M →ₗ[R] M₃) :

g ∘ₗ (a • f) = a • g ∘ₗ f

instance LinearMap.module {R : Type u_1} {R₂ : Type u_3} {S : Type u_5} {M : Type u_8} {M₂ : Type u_10} [Semiring R] [Semiring R₂] [AddCommMonoid M] [AddCommMonoid M₂] [Module R M] [Module R₂ M₂] {σ₁₂ : R →+* R₂} [Semiring S] [Module S M₂] [SMulCommClass R₂ S M₂] :

Module S (M →ₛₗ[σ₁₂] M₂)

Equations

@[simp]

theorem LinearMap.restrictScalars_zero (R : Type u_14) (S : Type u_15) (M : Type u_16) (N : Type u_17) [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid N] [Module R M] [Module R N] [Module S M] [Module S N] [CompatibleSMul M N R S] :

↑R 0 = 0

@[simp]

theorem LinearMap.restrictScalars_add {R : Type u_14} {S : Type u_15} {M : Type u_16} {N : Type u_17} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid N] [Module R M] [Module R N] [Module S M] [Module S N] [CompatibleSMul M N R S] (f g : M →ₗ[S] N) :

↑R (f + g) = ↑R f + ↑R g

@[simp]

theorem LinearMap.restrictScalars_neg {R : Type u_14} {S : Type u_15} [Semiring R] [Semiring S] {M : Type u_19} {N : Type u_20} [AddCommMonoid M] [AddCommGroup N] [Module R M] [Module R N] [Module S M] [Module S N] [CompatibleSMul M N R S] (f : M →ₗ[S] N) :

↑R (-f) = -↑R f

@[simp]

theorem LinearMap.restrictScalars_smul {R : Type u_14} {S : Type u_15} {M : Type u_16} {N : Type u_17} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid N] [Module R M] [Module R N] [Module S M] [Module S N] [CompatibleSMul M N R S] {R₁ : Type u_19} [Semiring R₁] [Module R₁ N] [SMulCommClass S R₁ N] [SMulCommClass R R₁ N] (c : R₁) (f : M →ₗ[S] N) :

↑R (c • f) = c • ↑R f

@[simp]

theorem LinearMap.restrictScalars_comp {R : Type u_14} {S : Type u_15} {M : Type u_16} {N : Type u_17} {P : Type u_18} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid N] [Module R M] [Module R N] [Module S M] [Module S N] [CompatibleSMul M N R S] [AddCommMonoid P] [Module S P] [Module R P] [CompatibleSMul N P R S] [CompatibleSMul M P R S] (f : N →ₗ[S] P) (g : M →ₗ[S] N) :

↑R (f ∘ₗ g) = ↑R f ∘ₗ ↑R g

@[simp]

theorem LinearMap.restrictScalars_trans {R : Type u_14} {S : Type u_15} {M : Type u_16} {N : Type u_17} [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid N] [Module R M] [Module R N] [Module S M] [Module S N] [CompatibleSMul M N R S] {T : Type u_20} [Semiring T] [Module T M] [Module T N] [CompatibleSMul M N S T] [CompatibleSMul M N R T] (f : M →ₗ[T] N) :

↑R (↑S f) = ↑R f

def LinearMap.restrictScalarsₗ (R : Type u_14) (S : Type u_15) (M : Type u_16) (N : Type u_17) [Semiring R] [Semiring S] [AddCommMonoid M] [AddCommMonoid N] [Module R M] [Module R N] [Module S M] [Module S N] [CompatibleSMul M N R S] (R₁ : Type u_19) [Semiring R₁] [Module R₁ N] [SMulCommClass S R₁ N] [SMulCommClass R R₁ N] :

(M →ₗ[S] N) →ₗ[R₁] M →ₗ[R] N

LinearMap.restrictScalars as a LinearMap.

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