Theorem ssdifd 3079

Description: If A is contained in B, then ( A \ C ) is contained in ( B \ C ). Deduction form of ssdif 3078. (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 3078	. 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 2914   C_ wss 2917

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022

This theorem depends on definitions:  df-bi 110  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-v 2559  df-dif 2920  df-in 2924  df-ss 2931

This theorem is referenced by:  ssdif2d  3082  phplem4dom  6324