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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 3589 | . . 3 ⊢ (𝐴 ⊆ 𝐵 ↔ 𝐴 = (𝐴 ∩ 𝐵)) | |
2 | df-in 3581 | . . . 4 ⊢ (𝐴 ∩ 𝐵) = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)} | |
3 | 2 | eqeq2i 2634 | . . 3 ⊢ (𝐴 = (𝐴 ∩ 𝐵) ↔ 𝐴 = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)}) |
4 | abeq2 2732 | . . 3 ⊢ (𝐴 = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)} ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) | |
5 | 1, 3, 4 | 3bitri 286 | . 2 ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) |
6 | pm4.71 662 | . . 3 ⊢ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ (𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) | |
7 | 6 | albii 1747 | . 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) |
8 | 5, 7 | bitr4i 267 | 1 ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 196 ∧ wa 384 ∀wal 1481 = wceq 1483 ∈ wcel 1990 {cab 2608 ∩ cin 3573 ⊆ wss 3574 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-clab 2609 df-cleq 2615 df-clel 2618 df-in 3581 df-ss 3588 |
This theorem is referenced by: dfss3 3592 dfss6 3593 dfss2f 3594 ssel 3597 ssriv 3607 ssrdv 3609 sstr2 3610 eqss 3618 nss 3663 rabss2 3685 ssconb 3743 ssequn1 3783 unss 3787 ssin 3835 ssdif0 3942 difin0ss 3946 inssdif0 3947 reldisj 4020 ssundif 4052 sbcssg 4085 pwss 4175 snss 4316 pwpw0 4344 pwsnALT 4429 ssuni 4459 ssuniOLD 4460 unissb 4469 iunss 4561 dftr2 4754 axpweq 4842 axpow2 4845 ssextss 4922 ssrel 5207 ssrelOLD 5208 ssrel2 5210 ssrelrel 5220 reliun 5239 relop 5272 issref 5509 funimass4 6247 dfom2 7067 inf2 8520 grothpw 9648 grothprim 9656 psslinpr 9853 ltaddpr 9856 isprm2 15395 vdwmc2 15683 acsmapd 17178 dfconn2 21222 iskgen3 21352 metcld 23104 metcld2 23105 isch2 28080 pjnormssi 29027 ssiun3 29376 ssrelf 29425 bnj1361 30899 bnj978 31019 dffr5 31643 brsset 31996 sscoid 32020 relowlpssretop 33212 rp-fakeinunass 37861 rababg 37879 ss2iundf 37951 dfhe3 38069 snhesn 38080 dffrege76 38233 ntrneiiso 38389 ntrneik2 38390 ntrneix2 38391 ntrneikb 38392 conss34OLD 38646 sbcssOLD 38756 onfrALTlem2 38761 trsspwALT 39045 trsspwALT2 39046 snssiALTVD 39062 snssiALT 39063 sstrALT2VD 39069 sstrALT2 39070 sbcssgVD 39119 onfrALTlem2VD 39125 sspwimp 39154 sspwimpVD 39155 sspwimpcf 39156 sspwimpcfVD 39157 sspwimpALT 39161 unisnALT 39162 iunssf 39263 icccncfext 40100 |
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