Description: Closed form of a deduction based on com3r . Proposition 14 of Frege1879 p. 37. (Contributed by RP, 24-Dec-2019) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | frege14 | |- ( ( ph -> ( ps -> ( ch -> ( th -> ta ) ) ) ) -> ( ph -> ( th -> ( ps -> ( ch -> ta ) ) ) ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | frege13 | |- ( ( ps -> ( ch -> ( th -> ta ) ) ) -> ( th -> ( ps -> ( ch -> ta ) ) ) ) |
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2 | frege5 | |- ( ( ( ps -> ( ch -> ( th -> ta ) ) ) -> ( th -> ( ps -> ( ch -> ta ) ) ) ) -> ( ( ph -> ( ps -> ( ch -> ( th -> ta ) ) ) ) -> ( ph -> ( th -> ( ps -> ( ch -> ta ) ) ) ) ) ) |
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3 | 1 2 | ax-mp | |- ( ( ph -> ( ps -> ( ch -> ( th -> ta ) ) ) ) -> ( ph -> ( th -> ( ps -> ( ch -> ta ) ) ) ) ) |