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Mirrors > Home > MPE Home > Th. List > dfss2 | Structured version Visualization version GIF version |
Description: Alternate definition of the subclass relationship between two classes. Definition 5.9 of [TakeutiZaring] p. 17. (Contributed by NM, 8-Jan-2002.) |
Ref | Expression |
---|---|
dfss2 | ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfss 3555 | . . 3 ⊢ (𝐴 ⊆ 𝐵 ↔ 𝐴 = (𝐴 ∩ 𝐵)) | |
2 | df-in 3547 | . . . 4 ⊢ (𝐴 ∩ 𝐵) = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)} | |
3 | 2 | eqeq2i 2622 | . . 3 ⊢ (𝐴 = (𝐴 ∩ 𝐵) ↔ 𝐴 = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)}) |
4 | abeq2 2719 | . . 3 ⊢ (𝐴 = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)} ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) | |
5 | 1, 3, 4 | 3bitri 285 | . 2 ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) |
6 | pm4.71 660 | . . 3 ⊢ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ (𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) | |
7 | 6 | albii 1737 | . 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) |
8 | 5, 7 | bitr4i 266 | 1 ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 195 ∧ wa 383 ∀wal 1473 = wceq 1475 ∈ wcel 1977 {cab 2596 ∩ cin 3539 ⊆ wss 3540 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 |
This theorem depends on definitions: df-bi 196 df-or 384 df-an 385 df-tru 1478 df-ex 1696 df-nf 1701 df-sb 1868 df-clab 2597 df-cleq 2603 df-clel 2606 df-in 3547 df-ss 3554 |
This theorem is referenced by: dfss3 3558 dfss2f 3559 ssel 3562 ssriv 3572 ssrdv 3574 sstr2 3575 eqss 3583 nss 3626 rabss2 3648 ssconb 3705 ssequn1 3745 unss 3749 ssin 3797 ssdif0 3896 difin0ss 3900 inssdif0 3901 reldisj 3972 ssundif 4004 sbcssg 4035 pwss 4123 snss 4259 pwpw0 4284 pwsnALT 4367 ssuni 4395 ssuniOLD 4396 unissb 4405 iunss 4497 dftr2 4682 axpweq 4768 axpow2 4771 ssextss 4849 ssrel 5130 ssrelOLD 5131 ssrel2 5133 ssrelrel 5143 reliun 5162 relop 5194 issref 5428 funimass4 6157 dfom2 6959 inf2 8403 grothpw 9527 grothprim 9535 psslinpr 9732 ltaddpr 9735 isprm2 15233 vdwmc2 15521 acsmapd 17001 dfcon2 21032 iskgen3 21162 metcld 22912 metcld2 22913 isch2 27464 pjnormssi 28411 ssiun3 28759 ssrelf 28805 bnj1361 30153 bnj978 30273 dffr5 30896 brsset 31166 sscoid 31190 relowlpssretop 32388 rp-fakeinunass 36880 rababg 36898 ss2iundf 36970 dfss6 37082 dfhe3 37089 snhesn 37100 dffrege76 37253 ntrneiiso 37409 ntrneik2 37410 ntrneix2 37411 ntrneikb 37412 conss34OLD 37667 sbcssOLD 37777 onfrALTlem2 37782 trsspwALT 38067 trsspwALT2 38068 snssiALTVD 38084 snssiALT 38085 sstrALT2VD 38091 sstrALT2 38092 sbcssgVD 38141 onfrALTlem2VD 38147 sspwimp 38176 sspwimpVD 38177 sspwimpcf 38178 sspwimpcfVD 38179 sspwimpALT 38183 unisnALT 38184 iunssf 38290 icccncfext 38773 |
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