Metamath Proof Explorer
Description: Subclass transitivity deduction. (Contributed by Jonathan Ben-Naim, 3-Jun-2011)
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Ref |
Expression |
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Hypotheses |
sseqtrid.1 |
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sseqtrid.2 |
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Assertion |
sseqtrid |
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Proof
Step |
Hyp |
Ref |
Expression |
1 |
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sseqtrid.1 |
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2 |
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sseqtrid.2 |
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3 |
1
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a1i |
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4 |
3 2
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sseqtrd |
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