Theorem cliftet

Description: show d is the same as an if-else involving a,b. (Contributed by Jarvin Udandy, 20-Sep-2020)

	Ref	Expression
Hypotheses	cliftet.1	|- ( ph /\ ch )
	cliftet.2	|- th
Assertion	cliftet	|- ( th <-> ( ( ph /\ ch ) \/ ( ps /\ -. ch ) ) )

Proof

Step	Hyp	Ref	Expression
1		cliftet.1	|- ( ph /\ ch )
2		cliftet.2	|- th
3	1	orci	|- ( ( ph /\ ch ) \/ ( ps /\ -. ch ) )
4	2 3	2th	|- ( th <-> ( ( ph /\ ch ) \/ ( ps /\ -. ch ) ) )