∫ Утверждение Mathlib
instCommSemigroup
Mathlib.Algebra.Group.Opposite
URI: https://scilib.ai/kg/mathlib#AddOpposite.instCommSemigroup
∫ Утверждение Mathlib
Mathlib.Algebra.Group.Opposite
URI: https://scilib.ai/kg/mathlib#AddOpposite.instCommSemigroup