The fundamental power operation in a monoid.
npowRec n a = a*a*...*a n times.
This function should not be used directly; it is often used to implement a Pow M Nat instance,
but end users should use the a ^ n notation instead.
The fundamental scalar multiplication in an additive monoid.
nsmulRec n a = a+a+...+a n times.
This function should not be used directly;
it is often used to implement an instance for scalar multiplication.