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Mirrors > Home > MPE Home > Th. List > Mathboxes > derang0 | Structured version Visualization version GIF version |
Description: The derangement number of the empty set. (Contributed by Mario Carneiro, 19-Jan-2015.) |
Ref | Expression |
---|---|
derang.d | ⊢ 𝐷 = (𝑥 ∈ Fin ↦ (♯‘{𝑓 ∣ (𝑓:𝑥–1-1-onto→𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) ≠ 𝑦)})) |
Ref | Expression |
---|---|
derang0 | ⊢ (𝐷‘∅) = 1 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0fin 8740 | . . 3 ⊢ ∅ ∈ Fin | |
2 | derang.d | . . . 4 ⊢ 𝐷 = (𝑥 ∈ Fin ↦ (♯‘{𝑓 ∣ (𝑓:𝑥–1-1-onto→𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) ≠ 𝑦)})) | |
3 | 2 | derangval 32409 | . . 3 ⊢ (∅ ∈ Fin → (𝐷‘∅) = (♯‘{𝑓 ∣ (𝑓:∅–1-1-onto→∅ ∧ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦)})) |
4 | 1, 3 | ax-mp 5 | . 2 ⊢ (𝐷‘∅) = (♯‘{𝑓 ∣ (𝑓:∅–1-1-onto→∅ ∧ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦)}) |
5 | ral0 4455 | . . . . . . 7 ⊢ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦 | |
6 | 5 | biantru 532 | . . . . . 6 ⊢ (𝑓:∅–1-1-onto→∅ ↔ (𝑓:∅–1-1-onto→∅ ∧ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦)) |
7 | eqid 2821 | . . . . . . 7 ⊢ ∅ = ∅ | |
8 | f1o00 6643 | . . . . . . 7 ⊢ (𝑓:∅–1-1-onto→∅ ↔ (𝑓 = ∅ ∧ ∅ = ∅)) | |
9 | 7, 8 | mpbiran2 708 | . . . . . 6 ⊢ (𝑓:∅–1-1-onto→∅ ↔ 𝑓 = ∅) |
10 | 6, 9 | bitr3i 279 | . . . . 5 ⊢ ((𝑓:∅–1-1-onto→∅ ∧ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦) ↔ 𝑓 = ∅) |
11 | 10 | abbii 2886 | . . . 4 ⊢ {𝑓 ∣ (𝑓:∅–1-1-onto→∅ ∧ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦)} = {𝑓 ∣ 𝑓 = ∅} |
12 | df-sn 4561 | . . . 4 ⊢ {∅} = {𝑓 ∣ 𝑓 = ∅} | |
13 | 11, 12 | eqtr4i 2847 | . . 3 ⊢ {𝑓 ∣ (𝑓:∅–1-1-onto→∅ ∧ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦)} = {∅} |
14 | 13 | fveq2i 6667 | . 2 ⊢ (♯‘{𝑓 ∣ (𝑓:∅–1-1-onto→∅ ∧ ∀𝑦 ∈ ∅ (𝑓‘𝑦) ≠ 𝑦)}) = (♯‘{∅}) |
15 | 0ex 5203 | . . 3 ⊢ ∅ ∈ V | |
16 | hashsng 13724 | . . 3 ⊢ (∅ ∈ V → (♯‘{∅}) = 1) | |
17 | 15, 16 | ax-mp 5 | . 2 ⊢ (♯‘{∅}) = 1 |
18 | 4, 14, 17 | 3eqtri 2848 | 1 ⊢ (𝐷‘∅) = 1 |
Colors of variables: wff setvar class |
Syntax hints: ∧ wa 398 = wceq 1533 ∈ wcel 2110 {cab 2799 ≠ wne 3016 ∀wral 3138 Vcvv 3494 ∅c0 4290 {csn 4560 ↦ cmpt 5138 –1-1-onto→wf1o 6348 ‘cfv 6349 Fincfn 8503 1c1 10532 ♯chash 13684 |
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 5195 ax-nul 5202 ax-pow 5258 ax-pr 5321 ax-un 7455 ax-cnex 10587 ax-resscn 10588 ax-1cn 10589 ax-icn 10590 ax-addcl 10591 ax-addrcl 10592 ax-mulcl 10593 ax-mulrcl 10594 ax-mulcom 10595 ax-addass 10596 ax-mulass 10597 ax-distr 10598 ax-i2m1 10599 ax-1ne0 10600 ax-1rid 10601 ax-rnegex 10602 ax-rrecex 10603 ax-cnre 10604 ax-pre-lttri 10605 ax-pre-lttrn 10606 ax-pre-ltadd 10607 ax-pre-mulgt0 10608 |
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-nel 3124 df-ral 3143 df-rex 3144 df-reu 3145 df-rab 3147 df-v 3496 df-sbc 3772 df-csb 3883 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 4561 df-pr 4563 df-tp 4565 df-op 4567 df-uni 4832 df-int 4869 df-iun 4913 df-br 5059 df-opab 5121 df-mpt 5139 df-tr 5165 df-id 5454 df-eprel 5459 df-po 5468 df-so 5469 df-fr 5508 df-we 5510 df-xp 5555 df-rel 5556 df-cnv 5557 df-co 5558 df-dm 5559 df-rn 5560 df-res 5561 df-ima 5562 df-pred 6142 df-ord 6188 df-on 6189 df-lim 6190 df-suc 6191 df-iota 6308 df-fun 6351 df-fn 6352 df-f 6353 df-f1 6354 df-fo 6355 df-f1o 6356 df-fv 6357 df-riota 7108 df-ov 7153 df-oprab 7154 df-mpo 7155 df-om 7575 df-1st 7683 df-2nd 7684 df-wrecs 7941 df-recs 8002 df-rdg 8040 df-1o 8096 df-er 8283 df-en 8504 df-dom 8505 df-sdom 8506 df-fin 8507 df-card 9362 df-pnf 10671 df-mnf 10672 df-xr 10673 df-ltxr 10674 df-le 10675 df-sub 10866 df-neg 10867 df-nn 11633 df-n0 11892 df-z 11976 df-uz 12238 df-fz 12887 df-hash 13685 |
This theorem is referenced by: subfac0 32419 |
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