Metamath Proof Explorer


Theorem xpss2

Description: Subset relation for Cartesian product. (Contributed by Jeff Hankins, 30-Aug-2009)

Ref Expression
Assertion xpss2 ⊢ A ⊆ B → C × A ⊆ C × B

Proof

Step Hyp Ref Expression
1 ssid ⊢ C ⊆ C
2 xpss12 ⊢ C ⊆ C ∧ A ⊆ B → C × A ⊆ C × B
3 1 2 mpan ⊢ A ⊆ B → C × A ⊆ C × B