Theorem ifpdfor 37809

Description: Define or in terms of conditional logic operator and true. (Contributed by RP, 20-Apr-2020.)

Assertion

Ref	Expression
ifpdfor	|- ( ( ph \/ ps ) <-> if- ( ph , T. , ps ) )

Proof of Theorem ifpdfor

Step	Hyp	Ref	Expression
1		tru 1487	. . . 4 |- T.
2	1	olci 406	. . 3 |- ( -. ph \/ T. )
3	2	biantrur 527	. 2 |- ( ( ph \/ ps ) <-> ( ( -. ph \/ T. ) /\ ( ph \/ ps ) ) )
4		dfifp4 1016	. 2 |- (if- ( ph , T. , ps ) <-> ( ( -. ph \/ T. ) /\ ( ph \/ ps ) ) )
5	3, 4	bitr4i 267	1 |- ( ( ph \/ ps ) <-> if- ( ph , T. , ps ) )

Syntax hints:   -. wn 3   <-> wb 196   \/ wo 383   /\ wa 384  if-wif 1012   T. wtru 1484

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-ifp 1013  df-tru 1486

This theorem is referenced by:  ifpdfxor  37832