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Mirrors > Home > MPE Home > Th. List > ssdomfi | Structured version Visualization version GIF version |
Description: A finite set dominates its subsets, proved without using the Axiom of Power Sets (unlike ssdomg 8995). (Contributed by BTernaryTau, 12-Nov-2024.) |
Ref | Expression |
---|---|
ssdomfi | ⊢ (𝐵 ∈ Fin → (𝐴 ⊆ 𝐵 → 𝐴 ≼ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | f1oi 6864 | . . . . 5 ⊢ ( I ↾ 𝐴):𝐴–1-1-onto→𝐴 | |
2 | f1of1 6825 | . . . . 5 ⊢ (( I ↾ 𝐴):𝐴–1-1-onto→𝐴 → ( I ↾ 𝐴):𝐴–1-1→𝐴) | |
3 | 1, 2 | ax-mp 5 | . . . 4 ⊢ ( I ↾ 𝐴):𝐴–1-1→𝐴 |
4 | f1ss 6786 | . . . 4 ⊢ ((( I ↾ 𝐴):𝐴–1-1→𝐴 ∧ 𝐴 ⊆ 𝐵) → ( I ↾ 𝐴):𝐴–1-1→𝐵) | |
5 | 3, 4 | mpan 687 | . . 3 ⊢ (𝐴 ⊆ 𝐵 → ( I ↾ 𝐴):𝐴–1-1→𝐵) |
6 | f1domfi 9183 | . . 3 ⊢ ((𝐵 ∈ Fin ∧ ( I ↾ 𝐴):𝐴–1-1→𝐵) → 𝐴 ≼ 𝐵) | |
7 | 5, 6 | sylan2 592 | . 2 ⊢ ((𝐵 ∈ Fin ∧ 𝐴 ⊆ 𝐵) → 𝐴 ≼ 𝐵) |
8 | 7 | ex 412 | 1 ⊢ (𝐵 ∈ Fin → (𝐴 ⊆ 𝐵 → 𝐴 ≼ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∈ wcel 2098 ⊆ wss 3943 class class class wbr 5141 I cid 5566 ↾ cres 5671 –1-1→wf1 6533 –1-1-onto→wf1o 6535 ≼ cdom 8936 Fincfn 8938 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2163 ax-ext 2697 ax-sep 5292 ax-nul 5299 ax-pr 5420 ax-un 7721 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2528 df-eu 2557 df-clab 2704 df-cleq 2718 df-clel 2804 df-nfc 2879 df-ne 2935 df-ral 3056 df-rex 3065 df-reu 3371 df-rab 3427 df-v 3470 df-sbc 3773 df-dif 3946 df-un 3948 df-in 3950 df-ss 3960 df-pss 3962 df-nul 4318 df-if 4524 df-pw 4599 df-sn 4624 df-pr 4626 df-op 4630 df-uni 4903 df-br 5142 df-opab 5204 df-tr 5259 df-id 5567 df-eprel 5573 df-po 5581 df-so 5582 df-fr 5624 df-we 5626 df-xp 5675 df-rel 5676 df-cnv 5677 df-co 5678 df-dm 5679 df-rn 5680 df-res 5681 df-ima 5682 df-ord 6360 df-on 6361 df-lim 6362 df-suc 6363 df-iota 6488 df-fun 6538 df-fn 6539 df-f 6540 df-f1 6541 df-fo 6542 df-f1o 6543 df-fv 6544 df-om 7852 df-1o 8464 df-en 8939 df-dom 8940 df-fin 8942 |
This theorem is referenced by: php 9209 php2 9210 |
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