3 ms·

This a topic that also comes up in linear algebra. Is there any analogy between vectors and types, or is the terminology just coincidental? https://en.wikipedia

• catnaroek 9y ago
  It's not a coincidence. The terms “covariance” and “contravariance” ultimately come from category theory.
  • jacobolus 9y ago
    According to Wikipedia: > The terms "covariant" and "contravariant" were introduced by James Joseph Sylvester in 1853 in the context of algebraic invariant theory, where, for instance, a system of simultaneous equations is contravariant in the variables. https://www.jstor.org/stable/108572 https://www.jstor.org/stable/108572
  • kmill 9y ago
    Next you're going to say "natural," "functor," and "category" come from category theory, too! :-)