Theorem imp_intro_ex ≪ | index | src | ≫

\imp引入\ex

theorem imp_intro_ex {x: set} (A B: wff x):
  $ A \imp B $ >
  $ \ex x A \imp \ex x B $;

Step	Hyp	Ref	Expression
1		fo_imp_insto_ex	\fo x (A \imp B) \imp \ex x A \imp \ex x B
2		hyp h	A \imp B
3	2	intro_fo	\fo x (A \imp B)
4	1, 3	ax_mp	\ex x A \imp \ex x B

Axiom use

Logic (ax_mp, ax_1, ax_2, ax_3, ax_gen, ax_4)