Theorem xpkeq1 4198

Description: Equality theorem for Kuratowski cross product. (Contributed by SF, 12-Jan-2015.)

Assertion

Ref	Expression
xpkeq1	⊢ (A = B → (A ×k C) = (B ×k C))

Proof of Theorem xpkeq1

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

Step	Hyp	Ref	Expression
1		rexeq 2808	. . 3 ⊢ (A = B → (∃y ∈ A ∃z ∈ C x = ⟪y, z⟫ ↔ ∃y ∈ B ∃z ∈ C x = ⟪y, z⟫))
2		elxpk2 4197	. . 3 ⊢ (x ∈ (A ×k C) ↔ ∃y ∈ A ∃z ∈ C x = ⟪y, z⟫)
3		elxpk2 4197	. . 3 ⊢ (x ∈ (B ×k C) ↔ ∃y ∈ B ∃z ∈ C x = ⟪y, z⟫)
4	1, 2, 3	3bitr4g 279	. 2 ⊢ (A = B → (x ∈ (A ×k C) ↔ x ∈ (B ×k C)))
5	4	eqrdv 2351	1 ⊢ (A = B → (A ×k C) = (B ×k C))

Syntax hints:   → wi 4   = wceq 1642   ∈ wcel 1710  ∃wrex 2615  ⟪copk 4057   ×_k cxpk 4174

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 4078  ax-sn 4087

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  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 2478  df-ne 2518  df-rex 2620  df-v 2861  df-nin 3211  df-compl 3212  df-in 3213  df-un 3214  df-dif 3215  df-ss 3259  df-nul 3551  df-sn 3741  df-pr 3742  df-opk 4058  df-xpk 4185

This theorem is referenced by:  xpkeq12  4200  xpkeq1i  4201  xpkeq1d  4204