Theorem iils ≪ | index | src | ≫

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

Step	Hyp	Ref	Expression
1		ax_p2	(A \imp B \imp C) \imp (A \imp B) \imp A \imp C

Axiom use

ZFC (ax_p2)