Metamath Proof Explorer

Theorem exanOLD

Description: Obsolete proof of exan as of 19-Jun-2023. (Contributed by NM, 18-Aug-1993) (Proof shortened by Andrew Salmon, 25-May-2011) (Proof shortened by Wolf Lammen, 13-Jan-2018) Reduce axiom dependencies. (Revised by BJ, 7-Jul-2021) (Proof shortened by Wolf Lammen, 6-Nov-2022) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypothesis exanOLD.1 x φ ψ
Assertion exanOLD x φ ψ


Step Hyp Ref Expression
1 exanOLD.1 x φ ψ
2 1 simpli x φ
3 1 simpri ψ
4 3 jctr φ φ ψ
5 2 4 eximii x φ ψ