Theorem opkelidkg 4275

Description: Membership in the Kuratowski identity relationship. (Contributed by SF, 13-Jan-2015.)

Assertion

Ref	Expression
opkelidkg	⊢ ((A ∈ V ∧ B ∈ W) → (⟪A, B⟫ ∈ Ik ↔ A = B))

Proof of Theorem opkelidkg

Dummy variables x y z are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-idk 4196	. 2 ⊢ Ik = {z ∣ ∃x∃y(z = ⟪x, y⟫ ∧ x = y)}
2		eqeq1 2359	. 2 ⊢ (x = A → (x = y ↔ A = y))
3		eqeq2 2362	. 2 ⊢ (y = B → (A = y ↔ A = B))
4	1, 2, 3	opkelopkabg 4246	1 ⊢ ((A ∈ V ∧ B ∈ W) → (⟪A, B⟫ ∈ Ik ↔ A = B))

Syntax hints:   → wi 4   ↔ wb 176   ∧ wa 358   = wceq 1642   ∈ wcel 1710  ⟪copk 4058   I_k cidk 4185

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4079  ax-sn 4088

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-ne 2519  df-v 2862  df-nin 3212  df-compl 3213  df-in 3214  df-un 3215  df-dif 3216  df-ss 3260  df-nul 3552  df-sn 3742  df-pr 3743  df-opk 4059  df-idk 4196

This theorem is referenced by:  dfidk2  4314  nnsucelrlem1  4425  nndisjeq  4430  eqtfinrelk  4487  oddfinex  4505  evenodddisjlem1  4516  dfphi2  4570