Theorem ssdifd 3345

Description: If A is contained in B, then ( A \ C ) is contained in ( B \ C ). Deduction form of ssdif 3344. (Contributed by David Moews, 1-May-2017.)

Hypothesis

Ref	Expression
ssdifd.1	|- ( ph -> A C_ B )

Assertion

Ref	Expression
ssdifd	|- ( ph -> ( A \ C ) C_ ( B \ C ) )

Proof of Theorem ssdifd

Step	Hyp	Ref	Expression
1		ssdifd.1	. 2 |- ( ph -> A C_ B )
2		ssdif 3344	. 2 |- ( A C_ B -> ( A \ C ) C_ ( B \ C ) )
3	1, 2	syl 14	1 |- ( ph -> ( A \ C ) C_ ( B \ C ) )

Syntax hints:   -> wi 4   \ cdif 3198   C_ wss 3201

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-in1 619  ax-in2 620  ax-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2213

This theorem depends on definitions:  df-bi 117  df-tru 1401  df-nf 1510  df-sb 1811  df-clab 2218  df-cleq 2224  df-clel 2227  df-nfc 2364  df-v 2805  df-dif 3203  df-in 3207  df-ss 3214

This theorem is referenced by:  ssdif2d  3348  phplem4dom  7091  fisseneq  7170