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Mirrors > Home > ILE Home > Th. List > enen2 | GIF version |
Description: Equality-like theorem for equinumerosity. (Contributed by NM, 18-Dec-2003.) |
Ref | Expression |
---|---|
enen2 | ⊢ (𝐴 ≈ 𝐵 → (𝐶 ≈ 𝐴 ↔ 𝐶 ≈ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | entr 6784 | . . 3 ⊢ ((𝐶 ≈ 𝐴 ∧ 𝐴 ≈ 𝐵) → 𝐶 ≈ 𝐵) | |
2 | 1 | ancoms 268 | . 2 ⊢ ((𝐴 ≈ 𝐵 ∧ 𝐶 ≈ 𝐴) → 𝐶 ≈ 𝐵) |
3 | ensym 6781 | . . 3 ⊢ (𝐴 ≈ 𝐵 → 𝐵 ≈ 𝐴) | |
4 | entr 6784 | . . . 4 ⊢ ((𝐶 ≈ 𝐵 ∧ 𝐵 ≈ 𝐴) → 𝐶 ≈ 𝐴) | |
5 | 4 | ancoms 268 | . . 3 ⊢ ((𝐵 ≈ 𝐴 ∧ 𝐶 ≈ 𝐵) → 𝐶 ≈ 𝐴) |
6 | 3, 5 | sylan 283 | . 2 ⊢ ((𝐴 ≈ 𝐵 ∧ 𝐶 ≈ 𝐵) → 𝐶 ≈ 𝐴) |
7 | 2, 6 | impbida 596 | 1 ⊢ (𝐴 ≈ 𝐵 → (𝐶 ≈ 𝐴 ↔ 𝐶 ≈ 𝐵)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 105 class class class wbr 4004 ≈ cen 6738 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 709 ax-5 1447 ax-7 1448 ax-gen 1449 ax-ie1 1493 ax-ie2 1494 ax-8 1504 ax-10 1505 ax-11 1506 ax-i12 1507 ax-bndl 1509 ax-4 1510 ax-17 1526 ax-i9 1530 ax-ial 1534 ax-i5r 1535 ax-13 2150 ax-14 2151 ax-ext 2159 ax-sep 4122 ax-pow 4175 ax-pr 4210 ax-un 4434 |
This theorem depends on definitions: df-bi 117 df-3an 980 df-tru 1356 df-nf 1461 df-sb 1763 df-eu 2029 df-mo 2030 df-clab 2164 df-cleq 2170 df-clel 2173 df-nfc 2308 df-ral 2460 df-rex 2461 df-v 2740 df-un 3134 df-in 3136 df-ss 3143 df-pw 3578 df-sn 3599 df-pr 3600 df-op 3602 df-uni 3811 df-br 4005 df-opab 4066 df-id 4294 df-xp 4633 df-rel 4634 df-cnv 4635 df-co 4636 df-dm 4637 df-rn 4638 df-res 4639 df-ima 4640 df-fun 5219 df-fn 5220 df-f 5221 df-f1 5222 df-fo 5223 df-f1o 5224 df-er 6535 df-en 6741 |
This theorem is referenced by: php5fin 6882 carden2bex 7188 hashen 10764 |
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