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Theorem eldifpr 3631
Description: Membership in a set with two elements removed. Similar to eldifsn 3731 and eldiftp 3650. (Contributed by Mario Carneiro, 18-Jul-2017.)
Assertion
Ref Expression
eldifpr (𝐴 ∈ (𝐵 ∖ {𝐶, 𝐷}) ↔ (𝐴𝐵𝐴𝐶𝐴𝐷))

Proof of Theorem eldifpr
StepHypRef Expression
1 elprg 3624 . . . . 5 (𝐴𝐵 → (𝐴 ∈ {𝐶, 𝐷} ↔ (𝐴 = 𝐶𝐴 = 𝐷)))
21notbid 668 . . . 4 (𝐴𝐵 → (¬ 𝐴 ∈ {𝐶, 𝐷} ↔ ¬ (𝐴 = 𝐶𝐴 = 𝐷)))
3 neanior 2444 . . . 4 ((𝐴𝐶𝐴𝐷) ↔ ¬ (𝐴 = 𝐶𝐴 = 𝐷))
42, 3bitr4di 198 . . 3 (𝐴𝐵 → (¬ 𝐴 ∈ {𝐶, 𝐷} ↔ (𝐴𝐶𝐴𝐷)))
54pm5.32i 454 . 2 ((𝐴𝐵 ∧ ¬ 𝐴 ∈ {𝐶, 𝐷}) ↔ (𝐴𝐵 ∧ (𝐴𝐶𝐴𝐷)))
6 eldif 3150 . 2 (𝐴 ∈ (𝐵 ∖ {𝐶, 𝐷}) ↔ (𝐴𝐵 ∧ ¬ 𝐴 ∈ {𝐶, 𝐷}))
7 3anass 983 . 2 ((𝐴𝐵𝐴𝐶𝐴𝐷) ↔ (𝐴𝐵 ∧ (𝐴𝐶𝐴𝐷)))
85, 6, 73bitr4i 212 1 (𝐴 ∈ (𝐵 ∖ {𝐶, 𝐷}) ↔ (𝐴𝐵𝐴𝐶𝐴𝐷))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wa 104  wb 105  wo 709  w3a 979   = wceq 1363  wcel 2158  wne 2357  cdif 3138  {cpr 3605
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 615  ax-in2 616  ax-io 710  ax-5 1457  ax-7 1458  ax-gen 1459  ax-ie1 1503  ax-ie2 1504  ax-8 1514  ax-10 1515  ax-11 1516  ax-i12 1517  ax-bndl 1519  ax-4 1520  ax-17 1536  ax-i9 1540  ax-ial 1544  ax-i5r 1545  ax-ext 2169
This theorem depends on definitions:  df-bi 117  df-3an 981  df-tru 1366  df-nf 1471  df-sb 1773  df-clab 2174  df-cleq 2180  df-clel 2183  df-nfc 2318  df-ne 2358  df-v 2751  df-dif 3143  df-un 3145  df-sn 3610  df-pr 3611
This theorem is referenced by:  rexdifpr  3632  rplogbval  14590
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