Metamath Proof Explorer


Theorem ifpan23

Description: Conjunction of conditional logical operators. (Contributed by RP, 20-Apr-2020)

Ref Expression
Assertion ifpan23 if-φψχif-φθτif-φψθχτ

Proof

Step Hyp Ref Expression
1 ifpan123g if-φψχif-φθτ¬φψφχ¬φθφτ
2 an4 ¬φψφχ¬φθφτ¬φψ¬φθφχφτ
3 dfifp4 if-φψθχτ¬φψθφχτ
4 ordi ¬φψθ¬φψ¬φθ
5 ordi φχτφχφτ
6 4 5 anbi12i ¬φψθφχτ¬φψ¬φθφχφτ
7 3 6 bitr2i ¬φψ¬φθφχφτif-φψθχτ
8 1 2 7 3bitri if-φψχif-φθτif-φψθχτ