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Theorem ssin 3245
Description: Subclass of intersection. Theorem 2.8(vii) of [Monk1] p. 26. (Contributed by NM, 15-Jun-2004.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)
Assertion
Ref Expression
ssin ((𝐴𝐵𝐴𝐶) ↔ 𝐴 ⊆ (𝐵𝐶))

Proof of Theorem ssin
Dummy variable 𝑥 is distinct from all other variables.
StepHypRef Expression
1 elin 3206 . . . . 5 (𝑥 ∈ (𝐵𝐶) ↔ (𝑥𝐵𝑥𝐶))
21imbi2i 225 . . . 4 ((𝑥𝐴𝑥 ∈ (𝐵𝐶)) ↔ (𝑥𝐴 → (𝑥𝐵𝑥𝐶)))
32albii 1414 . . 3 (∀𝑥(𝑥𝐴𝑥 ∈ (𝐵𝐶)) ↔ ∀𝑥(𝑥𝐴 → (𝑥𝐵𝑥𝐶)))
4 jcab 573 . . . 4 ((𝑥𝐴 → (𝑥𝐵𝑥𝐶)) ↔ ((𝑥𝐴𝑥𝐵) ∧ (𝑥𝐴𝑥𝐶)))
54albii 1414 . . 3 (∀𝑥(𝑥𝐴 → (𝑥𝐵𝑥𝐶)) ↔ ∀𝑥((𝑥𝐴𝑥𝐵) ∧ (𝑥𝐴𝑥𝐶)))
6 19.26 1425 . . 3 (∀𝑥((𝑥𝐴𝑥𝐵) ∧ (𝑥𝐴𝑥𝐶)) ↔ (∀𝑥(𝑥𝐴𝑥𝐵) ∧ ∀𝑥(𝑥𝐴𝑥𝐶)))
73, 5, 63bitrri 206 . 2 ((∀𝑥(𝑥𝐴𝑥𝐵) ∧ ∀𝑥(𝑥𝐴𝑥𝐶)) ↔ ∀𝑥(𝑥𝐴𝑥 ∈ (𝐵𝐶)))
8 dfss2 3036 . . 3 (𝐴𝐵 ↔ ∀𝑥(𝑥𝐴𝑥𝐵))
9 dfss2 3036 . . 3 (𝐴𝐶 ↔ ∀𝑥(𝑥𝐴𝑥𝐶))
108, 9anbi12i 451 . 2 ((𝐴𝐵𝐴𝐶) ↔ (∀𝑥(𝑥𝐴𝑥𝐵) ∧ ∀𝑥(𝑥𝐴𝑥𝐶)))
11 dfss2 3036 . 2 (𝐴 ⊆ (𝐵𝐶) ↔ ∀𝑥(𝑥𝐴𝑥 ∈ (𝐵𝐶)))
127, 10, 113bitr4i 211 1 ((𝐴𝐵𝐴𝐶) ↔ 𝐴 ⊆ (𝐵𝐶))
Colors of variables: wff set class
Syntax hints:  wi 4  wa 103  wb 104  wal 1297  wcel 1448  cin 3020  wss 3021
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 671  ax-5 1391  ax-7 1392  ax-gen 1393  ax-ie1 1437  ax-ie2 1438  ax-8 1450  ax-10 1451  ax-11 1452  ax-i12 1453  ax-bndl 1454  ax-4 1455  ax-17 1474  ax-i9 1478  ax-ial 1482  ax-i5r 1483  ax-ext 2082
This theorem depends on definitions:  df-bi 116  df-tru 1302  df-nf 1405  df-sb 1704  df-clab 2087  df-cleq 2093  df-clel 2096  df-nfc 2229  df-v 2643  df-in 3027  df-ss 3034
This theorem is referenced by:  ssini  3246  ssind  3247  uneqin  3274  trin  3976  pwin  4142  peano5  4450  fin  5245  tgval  12000  eltg3i  12007  innei  12114  cnptoprest2  12190
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