fact: Definition sig: Signature := single_sorted_signature (λ o, match o with zero | one => O | negate => 1%nat | plus | mult => 2%nat end).
imports: Coq.setoid_ring.Ring MathClasses.interfaces.abstract_algebra MathClasses.interfaces.universal_algebra MathClasses.theory.ua_homomorphisms MathClasses.misc.workaround_tactics