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Theorem map1 7101
Description: Set exponentiation: ordinal 1 to any set is equinumerous to ordinal 1. Exercise 4.42(b) of [Mendelson] p. 255. (Contributed by NM, 17-Dec-2003.)
Assertion
Ref Expression
map1 (𝐴𝑉 → (1o𝑚 𝐴) ≈ 1o)

Proof of Theorem map1
Dummy variables 𝑥 𝑦 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 fnmap 6929 . . 3 𝑚 Fn (V × V)
2 1oex 6695 . . 3 1o ∈ V
3 elex 2833 . . 3 (𝐴𝑉𝐴 ∈ V)
4 fnovex 6118 . . 3 (( ↑𝑚 Fn (V × V) ∧ 1o ∈ V ∧ 𝐴 ∈ V) → (1o𝑚 𝐴) ∈ V)
51, 2, 3, 4mp3an12i 1382 . 2 (𝐴𝑉 → (1o𝑚 𝐴) ∈ V)
62a1i 9 . 2 (𝐴𝑉 → 1o ∈ V)
7 0ex 4260 . . 3 ∅ ∈ V
872a1i 27 . 2 (𝐴𝑉 → (𝑥 ∈ (1o𝑚 𝐴) → ∅ ∈ V))
9 p0ex 4325 . . . 4 {∅} ∈ V
10 xpexg 4889 . . . 4 ((𝐴𝑉 ∧ {∅} ∈ V) → (𝐴 × {∅}) ∈ V)
119, 10mpan2 429 . . 3 (𝐴𝑉 → (𝐴 × {∅}) ∈ V)
1211a1d 22 . 2 (𝐴𝑉 → (𝑦 ∈ 1o → (𝐴 × {∅}) ∈ V))
13 el1o 6710 . . . . 5 (𝑦 ∈ 1o𝑦 = ∅)
1413a1i 9 . . . 4 (𝐴𝑉 → (𝑦 ∈ 1o𝑦 = ∅))
15 df1o2 6701 . . . . . . . 8 1o = {∅}
1615oveq1i 6095 . . . . . . 7 (1o𝑚 𝐴) = ({∅} ↑𝑚 𝐴)
1716eleq2i 2305 . . . . . 6 (𝑥 ∈ (1o𝑚 𝐴) ↔ 𝑥 ∈ ({∅} ↑𝑚 𝐴))
18 elmapg 6935 . . . . . . 7 (({∅} ∈ V ∧ 𝐴𝑉) → (𝑥 ∈ ({∅} ↑𝑚 𝐴) ↔ 𝑥:𝐴⟶{∅}))
199, 18mpan 428 . . . . . 6 (𝐴𝑉 → (𝑥 ∈ ({∅} ↑𝑚 𝐴) ↔ 𝑥:𝐴⟶{∅}))
2017, 19bitrid 192 . . . . 5 (𝐴𝑉 → (𝑥 ∈ (1o𝑚 𝐴) ↔ 𝑥:𝐴⟶{∅}))
217fconst2 5932 . . . . 5 (𝑥:𝐴⟶{∅} ↔ 𝑥 = (𝐴 × {∅}))
2220, 21bitr2di 197 . . . 4 (𝐴𝑉 → (𝑥 = (𝐴 × {∅}) ↔ 𝑥 ∈ (1o𝑚 𝐴)))
2314, 22anbi12d 477 . . 3 (𝐴𝑉 → ((𝑦 ∈ 1o𝑥 = (𝐴 × {∅})) ↔ (𝑦 = ∅ ∧ 𝑥 ∈ (1o𝑚 𝐴))))
24 ancom 266 . . 3 ((𝑦 = ∅ ∧ 𝑥 ∈ (1o𝑚 𝐴)) ↔ (𝑥 ∈ (1o𝑚 𝐴) ∧ 𝑦 = ∅))
2523, 24bitr2di 197 . 2 (𝐴𝑉 → ((𝑥 ∈ (1o𝑚 𝐴) ∧ 𝑦 = ∅) ↔ (𝑦 ∈ 1o𝑥 = (𝐴 × {∅}))))
265, 6, 8, 12, 25en2d 7054 1 (𝐴𝑉 → (1o𝑚 𝐴) ≈ 1o)
Colors of variables:    wff set class
This proof depends on syntax axioms:  wi 4  wa 104  wb 105   = wceq 1402  wcel 2209  Vcvv 2821  c0 3520  {csn 3709   class class class wbr 4130   × cxp 4772   Fn wfn 5372  wf 5373  (class class class)co 6085  1oc1o 6680  𝑚 cmap 6922  cen 7020
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 623  ax-in2 624  ax-io 721  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-10 1558  ax-11 1559  ax-i12 1560  ax-bndl 1562  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-14 2212  ax-ext 2220  ax-sep 4249  ax-nul 4259  ax-pow 4311  ax-pr 4346  ax-un 4578  ax-setind 4684
This proof depends on definitions:  df-bi 117  df-3an 1011  df-tru 1405  df-fal 1408  df-nf 1514  df-sb 1816  df-eu 2089  df-mo 2090  df-clab 2225  df-cleq 2231  df-clel 2234  df-nfc 2381  df-ne 2421  df-ral 2533  df-rex 2534  df-rab 2537  df-v 2823  df-sbc 3052  df-csb 3148  df-dif 3222  df-un 3224  df-in 3226  df-ss 3233  df-nul 3521  df-pw 3690  df-sn 3715  df-pr 3716  df-op 3718  df-uni 3936  df-iun 4014  df-br 4131  df-opab 4193  df-mpt 4194  df-tr 4230  df-id 4438  df-iord 4511  df-on 4513  df-suc 4516  df-xp 4780  df-rel 4781  df-cnv 4782  df-co 4783  df-dm 4784  df-rn 4785  df-res 4786  df-ima 4787  df-iota 5337  df-fun 5379  df-fn 5380  df-f 5381  df-f1 5382  df-fo 5383  df-f1o 5384  df-fv 5385  df-ov 6088  df-oprab 6089  df-mpo 6090  df-1st 6374  df-2nd 6375  df-1o 6687  df-map 6924  df-en 7023
This theorem is used by: (None)
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