Metamath Proof Explorer


Theorem frege15

Description: A closed form of com4r . Proposition 15 of Frege1879 p. 38. (Contributed by RP, 24-Dec-2019) (Proof modification is discouraged.)

Ref Expression
Assertion frege15 φ ψ χ θ τ θ φ ψ χ τ

Proof

Step Hyp Ref Expression
1 frege14 φ ψ χ θ τ φ θ ψ χ τ
2 frege12 φ ψ χ θ τ φ θ ψ χ τ φ ψ χ θ τ θ φ ψ χ τ
3 1 2 ax-mp φ ψ χ θ τ θ φ ψ χ τ