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Mirrors > Home > MPE Home > Th. List > hashres | Structured version Visualization version GIF version |
Description: The number of elements of a finite function restricted to a subset of its domain is equal to the number of elements of that subset. (Contributed by AV, 15-Dec-2021.) |
Ref | Expression |
---|---|
hashres | ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → (♯‘(𝐴 ↾ 𝐵)) = (♯‘𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | funres 6473 | . . . 4 ⊢ (Fun 𝐴 → Fun (𝐴 ↾ 𝐵)) | |
2 | 1 | 3ad2ant1 1132 | . . 3 ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → Fun (𝐴 ↾ 𝐵)) |
3 | finresfin 9021 | . . . . 5 ⊢ (𝐴 ∈ Fin → (𝐴 ↾ 𝐵) ∈ Fin) | |
4 | 3 | 3ad2ant2 1133 | . . . 4 ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → (𝐴 ↾ 𝐵) ∈ Fin) |
5 | hashfun 14148 | . . . 4 ⊢ ((𝐴 ↾ 𝐵) ∈ Fin → (Fun (𝐴 ↾ 𝐵) ↔ (♯‘(𝐴 ↾ 𝐵)) = (♯‘dom (𝐴 ↾ 𝐵)))) | |
6 | 4, 5 | syl 17 | . . 3 ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → (Fun (𝐴 ↾ 𝐵) ↔ (♯‘(𝐴 ↾ 𝐵)) = (♯‘dom (𝐴 ↾ 𝐵)))) |
7 | 2, 6 | mpbid 231 | . 2 ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → (♯‘(𝐴 ↾ 𝐵)) = (♯‘dom (𝐴 ↾ 𝐵))) |
8 | ssdmres 5912 | . . . . 5 ⊢ (𝐵 ⊆ dom 𝐴 ↔ dom (𝐴 ↾ 𝐵) = 𝐵) | |
9 | 8 | biimpi 215 | . . . 4 ⊢ (𝐵 ⊆ dom 𝐴 → dom (𝐴 ↾ 𝐵) = 𝐵) |
10 | 9 | 3ad2ant3 1134 | . . 3 ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → dom (𝐴 ↾ 𝐵) = 𝐵) |
11 | 10 | fveq2d 6773 | . 2 ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → (♯‘dom (𝐴 ↾ 𝐵)) = (♯‘𝐵)) |
12 | 7, 11 | eqtrd 2780 | 1 ⊢ ((Fun 𝐴 ∧ 𝐴 ∈ Fin ∧ 𝐵 ⊆ dom 𝐴) → (♯‘(𝐴 ↾ 𝐵)) = (♯‘𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ w3a 1086 = wceq 1542 ∈ wcel 2110 ⊆ wss 3892 dom cdm 5589 ↾ cres 5591 Fun wfun 6425 ‘cfv 6431 Fincfn 8714 ♯chash 14040 |
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-rep 5214 ax-sep 5227 ax-nul 5234 ax-pow 5292 ax-pr 5356 ax-un 7580 ax-cnex 10926 ax-resscn 10927 ax-1cn 10928 ax-icn 10929 ax-addcl 10930 ax-addrcl 10931 ax-mulcl 10932 ax-mulrcl 10933 ax-mulcom 10934 ax-addass 10935 ax-mulass 10936 ax-distr 10937 ax-i2m1 10938 ax-1ne0 10939 ax-1rid 10940 ax-rnegex 10941 ax-rrecex 10942 ax-cnre 10943 ax-pre-lttri 10944 ax-pre-lttrn 10945 ax-pre-ltadd 10946 ax-pre-mulgt0 10947 |
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-nel 3052 df-ral 3071 df-rex 3072 df-reu 3073 df-rab 3075 df-v 3433 df-sbc 3721 df-csb 3838 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-int 4886 df-iun 4932 df-br 5080 df-opab 5142 df-mpt 5163 df-tr 5197 df-id 5489 df-eprel 5495 df-po 5503 df-so 5504 df-fr 5544 df-we 5546 df-xp 5595 df-rel 5596 df-cnv 5597 df-co 5598 df-dm 5599 df-rn 5600 df-res 5601 df-ima 5602 df-pred 6200 df-ord 6267 df-on 6268 df-lim 6269 df-suc 6270 df-iota 6389 df-fun 6433 df-fn 6434 df-f 6435 df-f1 6436 df-fo 6437 df-f1o 6438 df-fv 6439 df-riota 7226 df-ov 7272 df-oprab 7273 df-mpo 7274 df-om 7705 df-1st 7822 df-2nd 7823 df-frecs 8086 df-wrecs 8117 df-recs 8191 df-rdg 8230 df-1o 8286 df-oadd 8290 df-er 8479 df-en 8715 df-dom 8716 df-sdom 8717 df-fin 8718 df-dju 9658 df-card 9696 df-pnf 11010 df-mnf 11011 df-xr 11012 df-ltxr 11013 df-le 11014 df-sub 11205 df-neg 11206 df-nn 11972 df-2 12034 df-n0 12232 df-xnn0 12304 df-z 12318 df-uz 12580 df-fz 13237 df-hash 14041 |
This theorem is referenced by: hashreshashfun 14150 |
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