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Mirrors > Home > MPE Home > Th. List > carden2 | Structured version Visualization version GIF version |
Description: Two numerable sets are equinumerous iff their cardinal numbers are equal. Unlike carden 9972, the Axiom of Choice is not required. (Contributed by Mario Carneiro, 22-Sep-2013.) |
Ref | Expression |
---|---|
carden2 | ⊢ ((𝐴 ∈ dom card ∧ 𝐵 ∈ dom card) → ((card‘𝐴) = (card‘𝐵) ↔ 𝐴 ≈ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | carddom2 9405 | . . 3 ⊢ ((𝐴 ∈ dom card ∧ 𝐵 ∈ dom card) → ((card‘𝐴) ⊆ (card‘𝐵) ↔ 𝐴 ≼ 𝐵)) | |
2 | carddom2 9405 | . . . 4 ⊢ ((𝐵 ∈ dom card ∧ 𝐴 ∈ dom card) → ((card‘𝐵) ⊆ (card‘𝐴) ↔ 𝐵 ≼ 𝐴)) | |
3 | 2 | ancoms 461 | . . 3 ⊢ ((𝐴 ∈ dom card ∧ 𝐵 ∈ dom card) → ((card‘𝐵) ⊆ (card‘𝐴) ↔ 𝐵 ≼ 𝐴)) |
4 | 1, 3 | anbi12d 632 | . 2 ⊢ ((𝐴 ∈ dom card ∧ 𝐵 ∈ dom card) → (((card‘𝐴) ⊆ (card‘𝐵) ∧ (card‘𝐵) ⊆ (card‘𝐴)) ↔ (𝐴 ≼ 𝐵 ∧ 𝐵 ≼ 𝐴))) |
5 | eqss 3981 | . . 3 ⊢ ((card‘𝐴) = (card‘𝐵) ↔ ((card‘𝐴) ⊆ (card‘𝐵) ∧ (card‘𝐵) ⊆ (card‘𝐴))) | |
6 | 5 | bicomi 226 | . 2 ⊢ (((card‘𝐴) ⊆ (card‘𝐵) ∧ (card‘𝐵) ⊆ (card‘𝐴)) ↔ (card‘𝐴) = (card‘𝐵)) |
7 | sbthb 8637 | . 2 ⊢ ((𝐴 ≼ 𝐵 ∧ 𝐵 ≼ 𝐴) ↔ 𝐴 ≈ 𝐵) | |
8 | 4, 6, 7 | 3bitr3g 315 | 1 ⊢ ((𝐴 ∈ dom card ∧ 𝐵 ∈ dom card) → ((card‘𝐴) = (card‘𝐵) ↔ 𝐴 ≈ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 = wceq 1533 ∈ wcel 2110 ⊆ wss 3935 class class class wbr 5065 dom cdm 5554 ‘cfv 6354 ≈ cen 8505 ≼ cdom 8506 cardccrd 9363 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 ax-sep 5202 ax-nul 5209 ax-pow 5265 ax-pr 5329 ax-un 7460 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-mo 2618 df-eu 2650 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ne 3017 df-ral 3143 df-rex 3144 df-rab 3147 df-v 3496 df-sbc 3772 df-dif 3938 df-un 3940 df-in 3942 df-ss 3951 df-pss 3953 df-nul 4291 df-if 4467 df-pw 4540 df-sn 4567 df-pr 4569 df-tp 4571 df-op 4573 df-uni 4838 df-int 4876 df-br 5066 df-opab 5128 df-mpt 5146 df-tr 5172 df-id 5459 df-eprel 5464 df-po 5473 df-so 5474 df-fr 5513 df-we 5515 df-xp 5560 df-rel 5561 df-cnv 5562 df-co 5563 df-dm 5564 df-rn 5565 df-res 5566 df-ima 5567 df-ord 6193 df-on 6194 df-iota 6313 df-fun 6356 df-fn 6357 df-f 6358 df-f1 6359 df-fo 6360 df-f1o 6361 df-fv 6362 df-er 8288 df-en 8509 df-dom 8510 df-sdom 8511 df-card 9367 |
This theorem is referenced by: cardsdom2 9416 pm54.43lem 9427 sdom2en01 9723 fin23lem22 9748 fin1a2lem9 9829 pwfseqlem4 10083 hashen 13706 |
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