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Mirrors > Home > ILE Home > Th. List > sseq2 | GIF version |
Description: Equality theorem for the subclass relationship. (Contributed by NM, 25-Jun-1998.) |
Ref | Expression |
---|---|
sseq2 | ⊢ (𝐴 = 𝐵 → (𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sstr2 3104 | . . . 4 ⊢ (𝐶 ⊆ 𝐴 → (𝐴 ⊆ 𝐵 → 𝐶 ⊆ 𝐵)) | |
2 | 1 | com12 30 | . . 3 ⊢ (𝐴 ⊆ 𝐵 → (𝐶 ⊆ 𝐴 → 𝐶 ⊆ 𝐵)) |
3 | sstr2 3104 | . . . 4 ⊢ (𝐶 ⊆ 𝐵 → (𝐵 ⊆ 𝐴 → 𝐶 ⊆ 𝐴)) | |
4 | 3 | com12 30 | . . 3 ⊢ (𝐵 ⊆ 𝐴 → (𝐶 ⊆ 𝐵 → 𝐶 ⊆ 𝐴)) |
5 | 2, 4 | anim12i 336 | . 2 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐵 ⊆ 𝐴) → ((𝐶 ⊆ 𝐴 → 𝐶 ⊆ 𝐵) ∧ (𝐶 ⊆ 𝐵 → 𝐶 ⊆ 𝐴))) |
6 | eqss 3112 | . 2 ⊢ (𝐴 = 𝐵 ↔ (𝐴 ⊆ 𝐵 ∧ 𝐵 ⊆ 𝐴)) | |
7 | dfbi2 385 | . 2 ⊢ ((𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵) ↔ ((𝐶 ⊆ 𝐴 → 𝐶 ⊆ 𝐵) ∧ (𝐶 ⊆ 𝐵 → 𝐶 ⊆ 𝐴))) | |
8 | 5, 6, 7 | 3imtr4i 200 | 1 ⊢ (𝐴 = 𝐵 → (𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ↔ wb 104 = wceq 1331 ⊆ wss 3071 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-11 1484 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 |
This theorem depends on definitions: df-bi 116 df-nf 1437 df-sb 1736 df-clab 2126 df-cleq 2132 df-clel 2135 df-in 3077 df-ss 3084 |
This theorem is referenced by: sseq12 3122 sseq2i 3124 sseq2d 3127 sseqtrid 3147 nssne1 3155 sseq0 3404 un00 3409 pweq 3513 ssintab 3788 ssintub 3789 intmin 3791 treq 4032 ssexg 4067 exmidundif 4129 frforeq3 4269 frirrg 4272 iunpw 4401 ordtri2orexmid 4438 ontr2exmid 4440 onsucsssucexmid 4442 ordtri2or2exmid 4486 fununi 5191 funcnvuni 5192 feq3 5257 ssimaexg 5483 nnawordex 6424 ereq1 6436 xpider 6500 domeng 6646 ssfiexmid 6770 fisseneq 6820 sbthlemi4 6848 sbthlemi5 6849 acfun 7063 ccfunen 7079 basis2 12215 eltg2 12222 clsval 12280 ntrcls0 12300 isnei 12313 neiint 12314 neipsm 12323 opnneissb 12324 opnssneib 12325 innei 12332 icnpimaex 12380 cnptoprest2 12409 neitx 12437 txcnp 12440 blssps 12596 blss 12597 metss 12663 metrest 12675 metcnp3 12680 bdssexg 13102 bj-nntrans 13149 bj-omtrans 13154 |
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