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Theorem ssfirab 6933
Description: A subset of a finite set is finite if it is defined by a decidable property. (Contributed by Jim Kingdon, 27-May-2022.)
Hypotheses
Ref Expression
ssfirab.a (𝜑𝐴 ∈ Fin)
ssfirab.dc (𝜑 → ∀𝑥𝐴 DECID 𝜓)
Assertion
Ref Expression
ssfirab (𝜑 → {𝑥𝐴𝜓} ∈ Fin)
Distinct variable group:   𝑥,𝐴
Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑥)

Proof of Theorem ssfirab
Dummy variables 𝑤 𝑦 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 rabeq 2730 . . 3 (𝑤 = ∅ → {𝑥𝑤𝜓} = {𝑥 ∈ ∅ ∣ 𝜓})
21eleq1d 2246 . 2 (𝑤 = ∅ → ({𝑥𝑤𝜓} ∈ Fin ↔ {𝑥 ∈ ∅ ∣ 𝜓} ∈ Fin))
3 rabeq 2730 . . 3 (𝑤 = 𝑦 → {𝑥𝑤𝜓} = {𝑥𝑦𝜓})
43eleq1d 2246 . 2 (𝑤 = 𝑦 → ({𝑥𝑤𝜓} ∈ Fin ↔ {𝑥𝑦𝜓} ∈ Fin))
5 rabeq 2730 . . 3 (𝑤 = (𝑦 ∪ {𝑧}) → {𝑥𝑤𝜓} = {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓})
65eleq1d 2246 . 2 (𝑤 = (𝑦 ∪ {𝑧}) → ({𝑥𝑤𝜓} ∈ Fin ↔ {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓} ∈ Fin))
7 rabeq 2730 . . 3 (𝑤 = 𝐴 → {𝑥𝑤𝜓} = {𝑥𝐴𝜓})
87eleq1d 2246 . 2 (𝑤 = 𝐴 → ({𝑥𝑤𝜓} ∈ Fin ↔ {𝑥𝐴𝜓} ∈ Fin))
9 rab0 3452 . . . 4 {𝑥 ∈ ∅ ∣ 𝜓} = ∅
10 0fin 6884 . . . 4 ∅ ∈ Fin
119, 10eqeltri 2250 . . 3 {𝑥 ∈ ∅ ∣ 𝜓} ∈ Fin
1211a1i 9 . 2 (𝜑 → {𝑥 ∈ ∅ ∣ 𝜓} ∈ Fin)
13 rabun2 3415 . . . . 5 {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓} = ({𝑥𝑦𝜓} ∪ {𝑥 ∈ {𝑧} ∣ 𝜓})
14 sbsbc 2967 . . . . . . . . . 10 ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜓)
15 vex 2741 . . . . . . . . . . 11 𝑧 ∈ V
16 ralsns 3631 . . . . . . . . . . 11 (𝑧 ∈ V → (∀𝑥 ∈ {𝑧}𝜓[𝑧 / 𝑥]𝜓))
1715, 16ax-mp 5 . . . . . . . . . 10 (∀𝑥 ∈ {𝑧}𝜓[𝑧 / 𝑥]𝜓)
1814, 17bitr4i 187 . . . . . . . . 9 ([𝑧 / 𝑥]𝜓 ↔ ∀𝑥 ∈ {𝑧}𝜓)
19 rabid2 2654 . . . . . . . . 9 ({𝑧} = {𝑥 ∈ {𝑧} ∣ 𝜓} ↔ ∀𝑥 ∈ {𝑧}𝜓)
2018, 19sylbb2 138 . . . . . . . 8 ([𝑧 / 𝑥]𝜓 → {𝑧} = {𝑥 ∈ {𝑧} ∣ 𝜓})
2120adantl 277 . . . . . . 7 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → {𝑧} = {𝑥 ∈ {𝑧} ∣ 𝜓})
2221uneq2d 3290 . . . . . 6 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → ({𝑥𝑦𝜓} ∪ {𝑧}) = ({𝑥𝑦𝜓} ∪ {𝑥 ∈ {𝑧} ∣ 𝜓}))
23 simplr 528 . . . . . . 7 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → {𝑥𝑦𝜓} ∈ Fin)
2415a1i 9 . . . . . . 7 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → 𝑧 ∈ V)
25 simprr 531 . . . . . . . . . 10 (((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) → 𝑧 ∈ (𝐴𝑦))
2625ad2antrr 488 . . . . . . . . 9 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → 𝑧 ∈ (𝐴𝑦))
2726eldifbd 3142 . . . . . . . 8 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → ¬ 𝑧𝑦)
28 elrabi 2891 . . . . . . . 8 (𝑧 ∈ {𝑥𝑦𝜓} → 𝑧𝑦)
2927, 28nsyl 628 . . . . . . 7 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → ¬ 𝑧 ∈ {𝑥𝑦𝜓})
30 unsnfi 6918 . . . . . . 7 (({𝑥𝑦𝜓} ∈ Fin ∧ 𝑧 ∈ V ∧ ¬ 𝑧 ∈ {𝑥𝑦𝜓}) → ({𝑥𝑦𝜓} ∪ {𝑧}) ∈ Fin)
3123, 24, 29, 30syl3anc 1238 . . . . . 6 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → ({𝑥𝑦𝜓} ∪ {𝑧}) ∈ Fin)
3222, 31eqeltrrd 2255 . . . . 5 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → ({𝑥𝑦𝜓} ∪ {𝑥 ∈ {𝑧} ∣ 𝜓}) ∈ Fin)
3313, 32eqeltrid 2264 . . . 4 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ [𝑧 / 𝑥]𝜓) → {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓} ∈ Fin)
34 ralsns 3631 . . . . . . . . . . . 12 (𝑧 ∈ V → (∀𝑥 ∈ {𝑧} ¬ 𝜓[𝑧 / 𝑥] ¬ 𝜓))
3515, 34ax-mp 5 . . . . . . . . . . 11 (∀𝑥 ∈ {𝑧} ¬ 𝜓[𝑧 / 𝑥] ¬ 𝜓)
36 sbsbc 2967 . . . . . . . . . . 11 ([𝑧 / 𝑥] ¬ 𝜓[𝑧 / 𝑥] ¬ 𝜓)
37 sbn 1952 . . . . . . . . . . 11 ([𝑧 / 𝑥] ¬ 𝜓 ↔ ¬ [𝑧 / 𝑥]𝜓)
3835, 36, 373bitr2ri 209 . . . . . . . . . 10 (¬ [𝑧 / 𝑥]𝜓 ↔ ∀𝑥 ∈ {𝑧} ¬ 𝜓)
39 rabeq0 3453 . . . . . . . . . 10 ({𝑥 ∈ {𝑧} ∣ 𝜓} = ∅ ↔ ∀𝑥 ∈ {𝑧} ¬ 𝜓)
4038, 39sylbb2 138 . . . . . . . . 9 (¬ [𝑧 / 𝑥]𝜓 → {𝑥 ∈ {𝑧} ∣ 𝜓} = ∅)
4140adantl 277 . . . . . . . 8 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ ¬ [𝑧 / 𝑥]𝜓) → {𝑥 ∈ {𝑧} ∣ 𝜓} = ∅)
4241uneq2d 3290 . . . . . . 7 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ ¬ [𝑧 / 𝑥]𝜓) → ({𝑥𝑦𝜓} ∪ {𝑥 ∈ {𝑧} ∣ 𝜓}) = ({𝑥𝑦𝜓} ∪ ∅))
43 un0 3457 . . . . . . 7 ({𝑥𝑦𝜓} ∪ ∅) = {𝑥𝑦𝜓}
4442, 43eqtrdi 2226 . . . . . 6 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ ¬ [𝑧 / 𝑥]𝜓) → ({𝑥𝑦𝜓} ∪ {𝑥 ∈ {𝑧} ∣ 𝜓}) = {𝑥𝑦𝜓})
4513, 44eqtrid 2222 . . . . 5 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ ¬ [𝑧 / 𝑥]𝜓) → {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓} = {𝑥𝑦𝜓})
46 simplr 528 . . . . 5 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ ¬ [𝑧 / 𝑥]𝜓) → {𝑥𝑦𝜓} ∈ Fin)
4745, 46eqeltrd 2254 . . . 4 (((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) ∧ ¬ [𝑧 / 𝑥]𝜓) → {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓} ∈ Fin)
48 simplrr 536 . . . . . . 7 ((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) → 𝑧 ∈ (𝐴𝑦))
4948eldifad 3141 . . . . . 6 ((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) → 𝑧𝐴)
50 ssfirab.dc . . . . . . 7 (𝜑 → ∀𝑥𝐴 DECID 𝜓)
5150ad3antrrr 492 . . . . . 6 ((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) → ∀𝑥𝐴 DECID 𝜓)
52 nfs1v 1939 . . . . . . . 8 𝑥[𝑧 / 𝑥]𝜓
5352nfdc 1659 . . . . . . 7 𝑥DECID [𝑧 / 𝑥]𝜓
54 sbequ12 1771 . . . . . . . 8 (𝑥 = 𝑧 → (𝜓 ↔ [𝑧 / 𝑥]𝜓))
5554dcbid 838 . . . . . . 7 (𝑥 = 𝑧 → (DECID 𝜓DECID [𝑧 / 𝑥]𝜓))
5653, 55rspc 2836 . . . . . 6 (𝑧𝐴 → (∀𝑥𝐴 DECID 𝜓DECID [𝑧 / 𝑥]𝜓))
5749, 51, 56sylc 62 . . . . 5 ((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) → DECID [𝑧 / 𝑥]𝜓)
58 exmiddc 836 . . . . 5 (DECID [𝑧 / 𝑥]𝜓 → ([𝑧 / 𝑥]𝜓 ∨ ¬ [𝑧 / 𝑥]𝜓))
5957, 58syl 14 . . . 4 ((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) → ([𝑧 / 𝑥]𝜓 ∨ ¬ [𝑧 / 𝑥]𝜓))
6033, 47, 59mpjaodan 798 . . 3 ((((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) ∧ {𝑥𝑦𝜓} ∈ Fin) → {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓} ∈ Fin)
6160ex 115 . 2 (((𝜑𝑦 ∈ Fin) ∧ (𝑦𝐴𝑧 ∈ (𝐴𝑦))) → ({𝑥𝑦𝜓} ∈ Fin → {𝑥 ∈ (𝑦 ∪ {𝑧}) ∣ 𝜓} ∈ Fin))
62 ssfirab.a . 2 (𝜑𝐴 ∈ Fin)
632, 4, 6, 8, 12, 61, 62findcard2sd 6892 1 (𝜑 → {𝑥𝐴𝜓} ∈ Fin)
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 104  wb 105  wo 708  DECID wdc 834   = wceq 1353  [wsb 1762  wcel 2148  wral 2455  {crab 2459  Vcvv 2738  [wsbc 2963  cdif 3127  cun 3128  wss 3130  c0 3423  {csn 3593  Fincfn 6740
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 614  ax-in2 615  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-13 2150  ax-14 2151  ax-ext 2159  ax-coll 4119  ax-sep 4122  ax-nul 4130  ax-pow 4175  ax-pr 4210  ax-un 4434  ax-setind 4537  ax-iinf 4588
This theorem depends on definitions:  df-bi 117  df-dc 835  df-3or 979  df-3an 980  df-tru 1356  df-fal 1359  df-nf 1461  df-sb 1763  df-eu 2029  df-mo 2030  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ne 2348  df-ral 2460  df-rex 2461  df-reu 2462  df-rab 2464  df-v 2740  df-sbc 2964  df-csb 3059  df-dif 3132  df-un 3134  df-in 3136  df-ss 3143  df-nul 3424  df-if 3536  df-pw 3578  df-sn 3599  df-pr 3600  df-op 3602  df-uni 3811  df-int 3846  df-iun 3889  df-br 4005  df-opab 4066  df-mpt 4067  df-tr 4103  df-id 4294  df-iord 4367  df-on 4369  df-suc 4372  df-iom 4591  df-xp 4633  df-rel 4634  df-cnv 4635  df-co 4636  df-dm 4637  df-rn 4638  df-res 4639  df-ima 4640  df-iota 5179  df-fun 5219  df-fn 5220  df-f 5221  df-f1 5222  df-fo 5223  df-f1o 5224  df-fv 5225  df-1o 6417  df-er 6535  df-en 6741  df-fin 6743
This theorem is referenced by:  ssfidc  6934  phivalfi  12212  hashdvds  12221  phiprmpw  12222  phimullem  12225  hashgcdeq  12239
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