Metamath Proof Explorer
Description: Identical to idd . Proposition 26 of Frege1879 p. 42. (Contributed by RP, 24-Dec-2019) (Proof modification is discouraged.)
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Ref |
Expression |
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Assertion |
frege26 |
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Proof
Step |
Hyp |
Ref |
Expression |
1 |
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ax-frege1 |
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2 |
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ax-frege8 |
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3 |
1 2
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ax-mp |
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