∫ Утверждение Mathlib
singleton_mem
Mathlib.SetTheory.Descriptive.Tree
URI: https://scilib.ai/kg/mathlib#Descriptive.Tree.singleton_mem
∫ Утверждение Mathlib
Mathlib.SetTheory.Descriptive.Tree
URI: https://scilib.ai/kg/mathlib#Descriptive.Tree.singleton_mem