Metamath Proof Explorer
Description: A specialized lemma for set theory (ordered pair theorem). (Contributed by NM, 18-Oct-1995) (Proof shortened by Wolf Lammen, 8-Dec-2012)
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Ref |
Expression |
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Hypotheses |
oplem1.1 |
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oplem1.2 |
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oplem1.3 |
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oplem1.4 |
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Assertion |
oplem1 |
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Proof
Step |
Hyp |
Ref |
Expression |
1 |
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oplem1.1 |
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2 |
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oplem1.2 |
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3 |
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oplem1.3 |
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4 |
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oplem1.4 |
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5 |
3
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notbii |
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6 |
1
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ord |
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7 |
5 6
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syl5bir |
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8 |
2
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ord |
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9 |
7 8
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jcad |
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10 |
4
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biimpar |
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11 |
9 10
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syl6 |
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12 |
11
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pm2.18d |
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13 |
12 3
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sylibr |
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