Metamath Proof Explorer


Theorem bnj982

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypotheses bnj982.1 φxφ
bnj982.2 ψxψ
bnj982.3 χxχ
bnj982.4 θxθ
Assertion bnj982 φψχθxφψχθ

Proof

Step Hyp Ref Expression
1 bnj982.1 φxφ
2 bnj982.2 ψxψ
3 bnj982.3 χxχ
4 bnj982.4 θxθ
5 df-bnj17 φψχθφψχθ
6 1 2 3 hb3an φψχxφψχ
7 6 4 hban φψχθxφψχθ
8 5 7 hbxfrbi φψχθxφψχθ