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Mirrors > Home > MPE Home > Th. List > Mathboxes > derangfmla | Structured version Visualization version GIF version |
Description: The derangements formula, which expresses the number of derangements of a finite nonempty set in terms of the factorial. The expression ⌊‘(𝑥 + 1 / 2) is a way of saying "rounded to the nearest integer". This is part of Metamath 100 proof #88. (Contributed by Mario Carneiro, 23-Jan-2015.) |
Ref | Expression |
---|---|
derangfmla.d | ⊢ 𝐷 = (𝑥 ∈ Fin ↦ (♯‘{𝑓 ∣ (𝑓:𝑥–1-1-onto→𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) ≠ 𝑦)})) |
Ref | Expression |
---|---|
derangfmla | ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≠ ∅) → (𝐷‘𝐴) = (⌊‘(((!‘(♯‘𝐴)) / e) + (1 / 2)))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | derangfmla.d | . . . 4 ⊢ 𝐷 = (𝑥 ∈ Fin ↦ (♯‘{𝑓 ∣ (𝑓:𝑥–1-1-onto→𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) ≠ 𝑦)})) | |
2 | oveq2 6932 | . . . . . 6 ⊢ (𝑛 = 𝑚 → (1...𝑛) = (1...𝑚)) | |
3 | 2 | fveq2d 6452 | . . . . 5 ⊢ (𝑛 = 𝑚 → (𝐷‘(1...𝑛)) = (𝐷‘(1...𝑚))) |
4 | 3 | cbvmptv 4987 | . . . 4 ⊢ (𝑛 ∈ ℕ0 ↦ (𝐷‘(1...𝑛))) = (𝑚 ∈ ℕ0 ↦ (𝐷‘(1...𝑚))) |
5 | 1, 4 | derangen2 31759 | . . 3 ⊢ (𝐴 ∈ Fin → (𝐷‘𝐴) = ((𝑛 ∈ ℕ0 ↦ (𝐷‘(1...𝑛)))‘(♯‘𝐴))) |
6 | 5 | adantr 474 | . 2 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≠ ∅) → (𝐷‘𝐴) = ((𝑛 ∈ ℕ0 ↦ (𝐷‘(1...𝑛)))‘(♯‘𝐴))) |
7 | hashnncl 13476 | . . . 4 ⊢ (𝐴 ∈ Fin → ((♯‘𝐴) ∈ ℕ ↔ 𝐴 ≠ ∅)) | |
8 | 7 | biimpar 471 | . . 3 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≠ ∅) → (♯‘𝐴) ∈ ℕ) |
9 | 1, 4 | subfacval3 31774 | . . 3 ⊢ ((♯‘𝐴) ∈ ℕ → ((𝑛 ∈ ℕ0 ↦ (𝐷‘(1...𝑛)))‘(♯‘𝐴)) = (⌊‘(((!‘(♯‘𝐴)) / e) + (1 / 2)))) |
10 | 8, 9 | syl 17 | . 2 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≠ ∅) → ((𝑛 ∈ ℕ0 ↦ (𝐷‘(1...𝑛)))‘(♯‘𝐴)) = (⌊‘(((!‘(♯‘𝐴)) / e) + (1 / 2)))) |
11 | 6, 10 | eqtrd 2814 | 1 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≠ ∅) → (𝐷‘𝐴) = (⌊‘(((!‘(♯‘𝐴)) / e) + (1 / 2)))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 386 = wceq 1601 ∈ wcel 2107 {cab 2763 ≠ wne 2969 ∀wral 3090 ∅c0 4141 ↦ cmpt 4967 –1-1-onto→wf1o 6136 ‘cfv 6137 (class class class)co 6924 Fincfn 8243 1c1 10275 + caddc 10277 / cdiv 11034 ℕcn 11378 2c2 11434 ℕ0cn0 11646 ...cfz 12647 ⌊cfl 12914 !cfa 13382 ♯chash 13439 eceu 15199 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1839 ax-4 1853 ax-5 1953 ax-6 2021 ax-7 2055 ax-8 2109 ax-9 2116 ax-10 2135 ax-11 2150 ax-12 2163 ax-13 2334 ax-ext 2754 ax-rep 5008 ax-sep 5019 ax-nul 5027 ax-pow 5079 ax-pr 5140 ax-un 7228 ax-inf2 8837 ax-cnex 10330 ax-resscn 10331 ax-1cn 10332 ax-icn 10333 ax-addcl 10334 ax-addrcl 10335 ax-mulcl 10336 ax-mulrcl 10337 ax-mulcom 10338 ax-addass 10339 ax-mulass 10340 ax-distr 10341 ax-i2m1 10342 ax-1ne0 10343 ax-1rid 10344 ax-rnegex 10345 ax-rrecex 10346 ax-cnre 10347 ax-pre-lttri 10348 ax-pre-lttrn 10349 ax-pre-ltadd 10350 ax-pre-mulgt0 10351 ax-pre-sup 10352 ax-addf 10353 ax-mulf 10354 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 837 df-3or 1072 df-3an 1073 df-tru 1605 df-fal 1615 df-ex 1824 df-nf 1828 df-sb 2012 df-mo 2551 df-eu 2587 df-clab 2764 df-cleq 2770 df-clel 2774 df-nfc 2921 df-ne 2970 df-nel 3076 df-ral 3095 df-rex 3096 df-reu 3097 df-rmo 3098 df-rab 3099 df-v 3400 df-sbc 3653 df-csb 3752 df-dif 3795 df-un 3797 df-in 3799 df-ss 3806 df-pss 3808 df-nul 4142 df-if 4308 df-pw 4381 df-sn 4399 df-pr 4401 df-tp 4403 df-op 4405 df-uni 4674 df-int 4713 df-iun 4757 df-br 4889 df-opab 4951 df-mpt 4968 df-tr 4990 df-id 5263 df-eprel 5268 df-po 5276 df-so 5277 df-fr 5316 df-se 5317 df-we 5318 df-xp 5363 df-rel 5364 df-cnv 5365 df-co 5366 df-dm 5367 df-rn 5368 df-res 5369 df-ima 5370 df-pred 5935 df-ord 5981 df-on 5982 df-lim 5983 df-suc 5984 df-iota 6101 df-fun 6139 df-fn 6140 df-f 6141 df-f1 6142 df-fo 6143 df-f1o 6144 df-fv 6145 df-isom 6146 df-riota 6885 df-ov 6927 df-oprab 6928 df-mpt2 6929 df-om 7346 df-1st 7447 df-2nd 7448 df-wrecs 7691 df-recs 7753 df-rdg 7791 df-1o 7845 df-2o 7846 df-oadd 7849 df-er 8028 df-map 8144 df-pm 8145 df-en 8244 df-dom 8245 df-sdom 8246 df-fin 8247 df-sup 8638 df-inf 8639 df-oi 8706 df-card 9100 df-cda 9327 df-pnf 10415 df-mnf 10416 df-xr 10417 df-ltxr 10418 df-le 10419 df-sub 10610 df-neg 10611 df-div 11035 df-nn 11379 df-2 11442 df-3 11443 df-4 11444 df-n0 11647 df-xnn0 11719 df-z 11733 df-uz 11997 df-q 12100 df-rp 12142 df-ico 12497 df-fz 12648 df-fzo 12789 df-fl 12916 df-seq 13124 df-exp 13183 df-fac 13383 df-bc 13412 df-hash 13440 df-shft 14218 df-cj 14250 df-re 14251 df-im 14252 df-sqrt 14386 df-abs 14387 df-limsup 14614 df-clim 14631 df-rlim 14632 df-sum 14829 df-ef 15204 df-e 15205 |
This theorem is referenced by: (None) |
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