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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 8778). (Contributed by BTernaryTau, 12-Nov-2024.) |
Ref | Expression |
---|---|
ssdomfi | ⊢ (𝐵 ∈ Fin → (𝐴 ⊆ 𝐵 → 𝐴 ≼ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | f1oi 6751 | . . . . 5 ⊢ ( I ↾ 𝐴):𝐴–1-1-onto→𝐴 | |
2 | f1of1 6713 | . . . . 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 6674 | . . . 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 8958 | . . 3 ⊢ ((𝐵 ∈ Fin ∧ ( I ↾ 𝐴):𝐴–1-1→𝐵) → 𝐴 ≼ 𝐵) | |
7 | 5, 6 | sylan2 593 | . 2 ⊢ ((𝐵 ∈ Fin ∧ 𝐴 ⊆ 𝐵) → 𝐴 ≼ 𝐵) |
8 | 7 | ex 413 | 1 ⊢ (𝐵 ∈ Fin → (𝐴 ⊆ 𝐵 → 𝐴 ≼ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∈ wcel 2110 ⊆ wss 3892 class class class wbr 5079 I cid 5489 ↾ cres 5592 –1-1→wf1 6429 –1-1-onto→wf1o 6431 ≼ cdom 8723 Fincfn 8725 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1802 ax-4 1816 ax-5 1917 ax-6 1975 ax-7 2015 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2158 ax-12 2175 ax-ext 2711 ax-sep 5227 ax-nul 5234 ax-pr 5356 ax-un 7583 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3or 1087 df-3an 1088 df-tru 1545 df-fal 1555 df-ex 1787 df-nf 1791 df-sb 2072 df-mo 2542 df-eu 2571 df-clab 2718 df-cleq 2732 df-clel 2818 df-nfc 2891 df-ne 2946 df-ral 3071 df-rex 3072 df-reu 3073 df-rab 3075 df-v 3433 df-sbc 3721 df-dif 3895 df-un 3897 df-in 3899 df-ss 3909 df-pss 3911 df-nul 4263 df-if 4466 df-pw 4541 df-sn 4568 df-pr 4570 df-op 4574 df-uni 4846 df-br 5080 df-opab 5142 df-tr 5197 df-id 5490 df-eprel 5496 df-po 5504 df-so 5505 df-fr 5545 df-we 5547 df-xp 5596 df-rel 5597 df-cnv 5598 df-co 5599 df-dm 5600 df-rn 5601 df-res 5602 df-ima 5603 df-ord 6268 df-on 6269 df-lim 6270 df-suc 6271 df-iota 6390 df-fun 6434 df-fn 6435 df-f 6436 df-f1 6437 df-fo 6438 df-f1o 6439 df-fv 6440 df-om 7708 df-1o 8289 df-en 8726 df-dom 8727 df-fin 8729 |
This theorem is referenced by: php 8983 php2 8984 |
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