Theorem ifpeq1d ≪ | index | src | ≫

theorem ifpeq1d (_G _p1 _p2 a b: wff):
  $ _G -> (_p1 <-> _p2) $ >
  $ _G -> (ifp _p1 a b <-> ifp _p2 a b) $;

Step	Hyp	Ref	Expression
1		hyp _h	_G -> (_p1 <-> _p2)
2		biidd	_G -> (a <-> a)
3		biidd	_G -> (b <-> b)
4	1, 2, 3	ifpeqd	_G -> (ifp _p1 a b <-> ifp _p2 a b)

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)