Theorem prnebg 4389

Description: A (proper) pair is not equal to another (maybe improper) pair if and only if an element of the first pair is not contained in the second pair. (Contributed by Alexander van der Vekens, 16-Jan-2018.)

Assertion

Ref	Expression
prnebg	|- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) /\ A =/= B ) -> ( ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) <-> { A , B } =/= { C , D } ) )

Proof of Theorem prnebg

Step	Hyp	Ref	Expression
1		prneimg 4388	. . 3 |- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) ) -> ( ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) -> { A , B } =/= { C , D } ) )
2	1	3adant3 1081	. 2 |- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) /\ A =/= B ) -> ( ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) -> { A , B } =/= { C , D } ) )
3		ioran 511	. . . . 5 |- ( -. ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) <-> ( -. ( A =/= C /\ A =/= D ) /\ -. ( B =/= C /\ B =/= D ) ) )
4		ianor 509	. . . . . . 7 |- ( -. ( A =/= C /\ A =/= D ) <-> ( -. A =/= C \/ -. A =/= D ) )
5		nne 2798	. . . . . . . 8 |- ( -. A =/= C <-> A = C )
6		nne 2798	. . . . . . . 8 |- ( -. A =/= D <-> A = D )
7	5, 6	orbi12i 543	. . . . . . 7 |- ( ( -. A =/= C \/ -. A =/= D ) <-> ( A = C \/ A = D ) )
8	4, 7	bitri 264	. . . . . 6 |- ( -. ( A =/= C /\ A =/= D ) <-> ( A = C \/ A = D ) )
9		ianor 509	. . . . . . 7 |- ( -. ( B =/= C /\ B =/= D ) <-> ( -. B =/= C \/ -. B =/= D ) )
10		nne 2798	. . . . . . . 8 |- ( -. B =/= C <-> B = C )
11		nne 2798	. . . . . . . 8 |- ( -. B =/= D <-> B = D )
12	10, 11	orbi12i 543	. . . . . . 7 |- ( ( -. B =/= C \/ -. B =/= D ) <-> ( B = C \/ B = D ) )
13	9, 12	bitri 264	. . . . . 6 |- ( -. ( B =/= C /\ B =/= D ) <-> ( B = C \/ B = D ) )
14	8, 13	anbi12i 733	. . . . 5 |- ( ( -. ( A =/= C /\ A =/= D ) /\ -. ( B =/= C /\ B =/= D ) ) <-> ( ( A = C \/ A = D ) /\ ( B = C \/ B = D ) ) )
15	3, 14	bitri 264	. . . 4 |- ( -. ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) <-> ( ( A = C \/ A = D ) /\ ( B = C \/ B = D ) ) )
16		anddi 914	. . . . 5 |- ( ( ( A = C \/ A = D ) /\ ( B = C \/ B = D ) ) <-> ( ( ( A = C /\ B = C ) \/ ( A = C /\ B = D ) ) \/ ( ( A = D /\ B = C ) \/ ( A = D /\ B = D ) ) ) )
17		eqtr3 2643	. . . . . . . . . 10 |- ( ( A = C /\ B = C ) -> A = B )
18		eqneqall 2805	. . . . . . . . . 10 |- ( A = B -> ( A =/= B -> { A , B } = { C , D } ) )
19	17, 18	syl 17	. . . . . . . . 9 |- ( ( A = C /\ B = C ) -> ( A =/= B -> { A , B } = { C , D } ) )
20		preq12 4270	. . . . . . . . . 10 |- ( ( A = C /\ B = D ) -> { A , B } = { C , D } )
21	20	a1d 25	. . . . . . . . 9 |- ( ( A = C /\ B = D ) -> ( A =/= B -> { A , B } = { C , D } ) )
22	19, 21	jaoi 394	. . . . . . . 8 |- ( ( ( A = C /\ B = C ) \/ ( A = C /\ B = D ) ) -> ( A =/= B -> { A , B } = { C , D } ) )
23		preq12 4270	. . . . . . . . . . 11 |- ( ( A = D /\ B = C ) -> { A , B } = { D , C } )
24		prcom 4267	. . . . . . . . . . 11 |- { D , C } = { C , D }
25	23, 24	syl6eq 2672	. . . . . . . . . 10 |- ( ( A = D /\ B = C ) -> { A , B } = { C , D } )
26	25	a1d 25	. . . . . . . . 9 |- ( ( A = D /\ B = C ) -> ( A =/= B -> { A , B } = { C , D } ) )
27		eqtr3 2643	. . . . . . . . . 10 |- ( ( A = D /\ B = D ) -> A = B )
28	27, 18	syl 17	. . . . . . . . 9 |- ( ( A = D /\ B = D ) -> ( A =/= B -> { A , B } = { C , D } ) )
29	26, 28	jaoi 394	. . . . . . . 8 |- ( ( ( A = D /\ B = C ) \/ ( A = D /\ B = D ) ) -> ( A =/= B -> { A , B } = { C , D } ) )
30	22, 29	jaoi 394	. . . . . . 7 |- ( ( ( ( A = C /\ B = C ) \/ ( A = C /\ B = D ) ) \/ ( ( A = D /\ B = C ) \/ ( A = D /\ B = D ) ) ) -> ( A =/= B -> { A , B } = { C , D } ) )
31	30	com12 32	. . . . . 6 |- ( A =/= B -> ( ( ( ( A = C /\ B = C ) \/ ( A = C /\ B = D ) ) \/ ( ( A = D /\ B = C ) \/ ( A = D /\ B = D ) ) ) -> { A , B } = { C , D } ) )
32	31	3ad2ant3 1084	. . . . 5 |- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) /\ A =/= B ) -> ( ( ( ( A = C /\ B = C ) \/ ( A = C /\ B = D ) ) \/ ( ( A = D /\ B = C ) \/ ( A = D /\ B = D ) ) ) -> { A , B } = { C , D } ) )
33	16, 32	syl5bi 232	. . . 4 |- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) /\ A =/= B ) -> ( ( ( A = C \/ A = D ) /\ ( B = C \/ B = D ) ) -> { A , B } = { C , D } ) )
34	15, 33	syl5bi 232	. . 3 |- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) /\ A =/= B ) -> ( -. ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) -> { A , B } = { C , D } ) )
35	34	necon1ad 2811	. 2 |- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) /\ A =/= B ) -> ( { A , B } =/= { C , D } -> ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) ) )
36	2, 35	impbid 202	1 |- ( ( ( A e. U /\ B e. V ) /\ ( C e. X /\ D e. Y ) /\ A =/= B ) -> ( ( ( A =/= C /\ A =/= D ) \/ ( B =/= C /\ B =/= D ) ) <-> { A , B } =/= { C , D } ) )

Syntax hints:   -. wn 3   -> wi 4   <-> wb 196   \/ wo 383   /\ wa 384   /\ w3a 1037   = wceq 1483   e. wcel 1990   =/= wne 2794   {cpr 4179

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-v 3202  df-un 3579  df-sn 4178  df-pr 4180

This theorem is referenced by:  zlmodzxznm  42286