Description: Lemma for pwfseq . Derive a final contradiction from the function F in pwfseqlem3 . Applying fpwwe2 to it, we get a certain maximal well-ordered subset Z , but the defining property ( Z F ( WZ ) ) e. Z contradicts our assumption on F , so we are reduced to the case of Z finite. This too is a contradiction, though, because Z and its preimage under ( WZ ) are distinct sets of the same cardinality and in a subset relation, which is impossible for finite sets. (Contributed by Mario Carneiro, 31-May-2015)
Ref | Expression | ||
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Hypotheses | pwfseqlem4.g | |
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pwfseqlem4.x | |
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pwfseqlem4.h | |
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pwfseqlem4.ps | |
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pwfseqlem4.k | |
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pwfseqlem4.d | |
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pwfseqlem4.f | |
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pwfseqlem4.w | |
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pwfseqlem4.z | |
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Assertion | pwfseqlem4 | |