fact: Definition second {x y z : C} (f : x ~> y) : z ⨂ x ~> z ⨂ y := fork proj_left (f ∘ proj_right).
imports: Category.Lib Category.Theory.Category Category.Theory.Isomorphism Category.Theory.Functor Category.Structure.Monoidal.Relevance Category.Structure.Monoidal.Semicartesian