Theorem ssres 4991

Description: Subclass theorem for restriction. (Contributed by set.mm contributors, 16-Aug-1994.)

Assertion

Ref	Expression
ssres	⊢ (A ⊆ B → (A ↾ C) ⊆ (B ↾ C))

Proof of Theorem ssres

Step	Hyp	Ref	Expression
1		ssrin 3481	. 2 ⊢ (A ⊆ B → (A ∩ (C × V)) ⊆ (B ∩ (C × V)))
2		df-res 4789	. 2 ⊢ (A ↾ C) = (A ∩ (C × V))
3		df-res 4789	. 2 ⊢ (B ↾ C) = (B ∩ (C × V))
4	1, 2, 3	3sstr4g 3313	1 ⊢ (A ⊆ B → (A ↾ C) ⊆ (B ↾ C))

Syntax hints:   → wi 4  Vcvv 2860   ∩ cin 3209   ⊆ wss 3258   × cxp 4771   ↾ cres 4775

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

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 2479  df-v 2862  df-nin 3212  df-compl 3213  df-in 3214  df-ss 3260  df-res 4789

This theorem is referenced by:  imass1  5024