Theorem dmxpss 5052

Description: The domain of a cross product is a subclass of the first factor. (Contributed by set.mm contributors, 19-Mar-2007.)

Assertion

Ref	Expression
dmxpss	|- dom (A X. B) C_ A

Proof of Theorem dmxpss

Step	Hyp	Ref	Expression
1		0ss 3579	. . 3 |- (/) C_ A
2		xpeq2 4799	. . . . . . 7 |- (B = (/) -> (A X. B) = (A X. (/)))
3		xp0 5044	. . . . . . 7 |- (A X. (/)) = (/)
4	2, 3	syl6eq 2401	. . . . . 6 |- (B = (/) -> (A X. B) = (/))
5	4	dmeqd 4909	. . . . 5 |- (B = (/) -> dom (A X. B) = dom (/))
6		dm0 4918	. . . . 5 |- dom (/) = (/)
7	5, 6	syl6eq 2401	. . . 4 |- (B = (/) -> dom (A X. B) = (/))
8	7	sseq1d 3298	. . 3 |- (B = (/) -> (dom (A X. B) C_ A <-> (/) C_ A))
9	1, 8	mpbiri 224	. 2 |- (B = (/) -> dom (A X. B) C_ A)
10		dmxp 4923	. . 3 |- (B =/= (/) -> dom (A X. B) = A)
11		eqimss 3323	. . 3 |- (dom (A X. B) = A -> dom (A X. B) C_ A)
12	10, 11	syl 15	. 2 |- (B =/= (/) -> dom (A X. B) C_ A)
13	9, 12	pm2.61ine 2592	1 |- dom (A X. B) C_ A

Syntax hints:   = wceq 1642   =/= wne 2516   C_ wss 3257  (/)c0 3550   X. cxp 4770  dom cdm 4772

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-13 1712  ax-14 1714  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4078  ax-xp 4079  ax-cnv 4080  ax-1c 4081  ax-sset 4082  ax-si 4083  ax-ins2 4084  ax-ins3 4085  ax-typlower 4086  ax-sn 4087

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-eu 2208  df-mo 2209  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-ne 2518  df-ral 2619  df-rex 2620  df-reu 2621  df-rmo 2622  df-rab 2623  df-v 2861  df-sbc 3047  df-nin 3211  df-compl 3212  df-in 3213  df-un 3214  df-dif 3215  df-symdif 3216  df-ss 3259  df-pss 3261  df-nul 3551  df-if 3663  df-pw 3724  df-sn 3741  df-pr 3742  df-uni 3892  df-int 3927  df-opk 4058  df-1c 4136  df-pw1 4137  df-uni1 4138  df-xpk 4185  df-cnvk 4186  df-ins2k 4187  df-ins3k 4188  df-imak 4189  df-cok 4190  df-p6 4191  df-sik 4192  df-ssetk 4193  df-imagek 4194  df-idk 4195  df-iota 4339  df-0c 4377  df-addc 4378  df-nnc 4379  df-fin 4380  df-lefin 4440  df-ltfin 4441  df-ncfin 4442  df-tfin 4443  df-evenfin 4444  df-oddfin 4445  df-sfin 4446  df-spfin 4447  df-phi 4565  df-op 4566  df-proj1 4567  df-proj2 4568  df-opab 4623  df-br 4640  df-ima 4727  df-xp 4784  df-cnv 4785  df-rn 4786  df-dm 4787

This theorem is referenced by:  rnxpss  5053  ssxpb  5055  funssxp  5233  dff3  5420  dmfrec  6316