Theorem imp_imp_insl ≪ | index | src | ≫

\imp左插入

theorem imp_imp_insl (A B C: wff):
  $ (A \imp B \imp C) \imp (A \imp B) \imp A \imp C $;

Step	Hyp	Ref	Expression
1		ax_2	(A \imp B \imp C) \imp (A \imp B) \imp A \imp C

Axiom use

Logic (ax_2)