ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  ss2iun GIF version

Theorem ss2iun 3927
Description: Subclass theorem for indexed union. (Contributed by NM, 26-Nov-2003.) (Proof shortened by Andrew Salmon, 25-Jul-2011.)
Assertion
Ref Expression
ss2iun (∀𝑥𝐴 𝐵𝐶 𝑥𝐴 𝐵 𝑥𝐴 𝐶)

Proof of Theorem ss2iun
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 ssel 3173 . . . . 5 (𝐵𝐶 → (𝑦𝐵𝑦𝐶))
21ralimi 2557 . . . 4 (∀𝑥𝐴 𝐵𝐶 → ∀𝑥𝐴 (𝑦𝐵𝑦𝐶))
3 rexim 2588 . . . 4 (∀𝑥𝐴 (𝑦𝐵𝑦𝐶) → (∃𝑥𝐴 𝑦𝐵 → ∃𝑥𝐴 𝑦𝐶))
42, 3syl 14 . . 3 (∀𝑥𝐴 𝐵𝐶 → (∃𝑥𝐴 𝑦𝐵 → ∃𝑥𝐴 𝑦𝐶))
5 eliun 3916 . . 3 (𝑦 𝑥𝐴 𝐵 ↔ ∃𝑥𝐴 𝑦𝐵)
6 eliun 3916 . . 3 (𝑦 𝑥𝐴 𝐶 ↔ ∃𝑥𝐴 𝑦𝐶)
74, 5, 63imtr4g 205 . 2 (∀𝑥𝐴 𝐵𝐶 → (𝑦 𝑥𝐴 𝐵𝑦 𝑥𝐴 𝐶))
87ssrdv 3185 1 (∀𝑥𝐴 𝐵𝐶 𝑥𝐴 𝐵 𝑥𝐴 𝐶)
Colors of variables: wff set class
Syntax hints:  wi 4  wcel 2164  wral 2472  wrex 2473  wss 3153   ciun 3912
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-io 710  ax-5 1458  ax-7 1459  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-8 1515  ax-10 1516  ax-11 1517  ax-i12 1518  ax-bndl 1520  ax-4 1521  ax-17 1537  ax-i9 1541  ax-ial 1545  ax-i5r 1546  ax-ext 2175
This theorem depends on definitions:  df-bi 117  df-tru 1367  df-nf 1472  df-sb 1774  df-clab 2180  df-cleq 2186  df-clel 2189  df-nfc 2325  df-ral 2477  df-rex 2478  df-v 2762  df-in 3159  df-ss 3166  df-iun 3914
This theorem is referenced by:  iuneq2  3928  abnexg  4477  imasaddvallemg  12898  dvfvalap  14835
  Copyright terms: Public domain W3C validator