Tests if a is zero.
Tests if a is zero.
Given a sequence of as, sum them using the monoid and return the total.
Given a sequence of as, sum them using the monoid and return the total.
Given a sequence of as, sum them using the semigroup and return the total.
Given a sequence of as, sum them using the semigroup and return the total.
If the sequence is empty, returns None. Otherwise, returns Some(total).
Return a added with itself n times.
Return a added with itself n times.
A module generalizes a vector space by requiring its scalar need only form a ring, rather than a field.