Metamath Proof Explorer


Theorem an13

Description: A rearrangement of conjuncts. (Contributed by NM, 24-Jun-2012) (Proof shortened by Wolf Lammen, 31-Dec-2012)

Ref Expression
Assertion an13 φ ψ χ χ ψ φ

Proof

Step Hyp Ref Expression
1 an21 ψ φ χ φ ψ χ
2 ancom ψ φ χ χ ψ φ
3 1 2 bitr3i φ ψ χ χ ψ φ