Theorem xaddass2 9872

Description: Associativity of extended real addition. See xaddass 9871 for notes on the hypotheses. (Contributed by Mario Carneiro, 20-Aug-2015.)

Assertion

Ref	Expression
xaddass2	|- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( ( A +e B ) +e C ) = ( A +e ( B +e C ) ) )

Proof of Theorem xaddass2

Step	Hyp	Ref	Expression
1		simp1l 1021	. . . . . 6 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> A e. RR* )
2		xnegcl 9834	. . . . . 6 |- ( A e. RR* -> -e A e. RR* )
3	1, 2	syl 14	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e A e. RR* )
4		simp1r 1022	. . . . . . 7 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> A =/= +oo )
5		pnfxr 8012	. . . . . . . . 9 |- +oo e. RR*
6		xneg11 9836	. . . . . . . . 9 |- ( ( A e. RR* /\ +oo e. RR* ) -> ( -e A = -e +oo <-> A = +oo ) )
7	1, 5, 6	sylancl 413	. . . . . . . 8 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e A = -e +oo <-> A = +oo ) )
8	7	necon3bid 2388	. . . . . . 7 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e A =/= -e +oo <-> A =/= +oo ) )
9	4, 8	mpbird 167	. . . . . 6 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e A =/= -e +oo )
10		xnegpnf 9830	. . . . . . 7 |- -e +oo = -oo
11	10	a1i 9	. . . . . 6 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e +oo = -oo )
12	9, 11	neeqtrd 2375	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e A =/= -oo )
13		simp2l 1023	. . . . . 6 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> B e. RR* )
14		xnegcl 9834	. . . . . 6 |- ( B e. RR* -> -e B e. RR* )
15	13, 14	syl 14	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e B e. RR* )
16		simp2r 1024	. . . . . . 7 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> B =/= +oo )
17		xneg11 9836	. . . . . . . . 9 |- ( ( B e. RR* /\ +oo e. RR* ) -> ( -e B = -e +oo <-> B = +oo ) )
18	13, 5, 17	sylancl 413	. . . . . . . 8 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e B = -e +oo <-> B = +oo ) )
19	18	necon3bid 2388	. . . . . . 7 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e B =/= -e +oo <-> B =/= +oo ) )
20	16, 19	mpbird 167	. . . . . 6 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e B =/= -e +oo )
21	20, 11	neeqtrd 2375	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e B =/= -oo )
22		simp3l 1025	. . . . . 6 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> C e. RR* )
23		xnegcl 9834	. . . . . 6 |- ( C e. RR* -> -e C e. RR* )
24	22, 23	syl 14	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e C e. RR* )
25		simp3r 1026	. . . . . . 7 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> C =/= +oo )
26		xneg11 9836	. . . . . . . . 9 |- ( ( C e. RR* /\ +oo e. RR* ) -> ( -e C = -e +oo <-> C = +oo ) )
27	22, 5, 26	sylancl 413	. . . . . . . 8 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e C = -e +oo <-> C = +oo ) )
28	27	necon3bid 2388	. . . . . . 7 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e C =/= -e +oo <-> C =/= +oo ) )
29	25, 28	mpbird 167	. . . . . 6 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e C =/= -e +oo )
30	29, 11	neeqtrd 2375	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e C =/= -oo )
31		xaddass 9871	. . . . 5 |- ( ( ( -e A e. RR* /\ -e A =/= -oo ) /\ ( -e B e. RR* /\ -e B =/= -oo ) /\ ( -e C e. RR* /\ -e C =/= -oo ) ) -> ( ( -e A +e -e B ) +e -e C ) = ( -e A +e ( -e B +e -e C ) ) )
32	3, 12, 15, 21, 24, 30, 31	syl222anc 1254	. . . 4 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( ( -e A +e -e B ) +e -e C ) = ( -e A +e ( -e B +e -e C ) ) )
33		xnegdi 9870	. . . . . 6 |- ( ( A e. RR* /\ B e. RR* ) -> -e ( A +e B ) = ( -e A +e -e B ) )
34	1, 13, 33	syl2anc 411	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e ( A +e B ) = ( -e A +e -e B ) )
35	34	oveq1d 5892	. . . 4 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e ( A +e B ) +e -e C ) = ( ( -e A +e -e B ) +e -e C ) )
36		xnegdi 9870	. . . . . 6 |- ( ( B e. RR* /\ C e. RR* ) -> -e ( B +e C ) = ( -e B +e -e C ) )
37	13, 22, 36	syl2anc 411	. . . . 5 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e ( B +e C ) = ( -e B +e -e C ) )
38	37	oveq2d 5893	. . . 4 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e A +e -e ( B +e C ) ) = ( -e A +e ( -e B +e -e C ) ) )
39	32, 35, 38	3eqtr4d 2220	. . 3 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e ( A +e B ) +e -e C ) = ( -e A +e -e ( B +e C ) ) )
40		xaddcl 9862	. . . . 5 |- ( ( A e. RR* /\ B e. RR* ) -> ( A +e B ) e. RR* )
41	1, 13, 40	syl2anc 411	. . . 4 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( A +e B ) e. RR* )
42		xnegdi 9870	. . . 4 |- ( ( ( A +e B ) e. RR* /\ C e. RR* ) -> -e ( ( A +e B ) +e C ) = ( -e ( A +e B ) +e -e C ) )
43	41, 22, 42	syl2anc 411	. . 3 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e ( ( A +e B ) +e C ) = ( -e ( A +e B ) +e -e C ) )
44		xaddcl 9862	. . . . 5 |- ( ( B e. RR* /\ C e. RR* ) -> ( B +e C ) e. RR* )
45	13, 22, 44	syl2anc 411	. . . 4 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( B +e C ) e. RR* )
46		xnegdi 9870	. . . 4 |- ( ( A e. RR* /\ ( B +e C ) e. RR* ) -> -e ( A +e ( B +e C ) ) = ( -e A +e -e ( B +e C ) ) )
47	1, 45, 46	syl2anc 411	. . 3 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e ( A +e ( B +e C ) ) = ( -e A +e -e ( B +e C ) ) )
48	39, 43, 47	3eqtr4d 2220	. 2 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> -e ( ( A +e B ) +e C ) = -e ( A +e ( B +e C ) ) )
49		xaddcl 9862	. . . 4 |- ( ( ( A +e B ) e. RR* /\ C e. RR* ) -> ( ( A +e B ) +e C ) e. RR* )
50	41, 22, 49	syl2anc 411	. . 3 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( ( A +e B ) +e C ) e. RR* )
51		xaddcl 9862	. . . 4 |- ( ( A e. RR* /\ ( B +e C ) e. RR* ) -> ( A +e ( B +e C ) ) e. RR* )
52	1, 45, 51	syl2anc 411	. . 3 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( A +e ( B +e C ) ) e. RR* )
53		xneg11 9836	. . 3 |- ( ( ( ( A +e B ) +e C ) e. RR* /\ ( A +e ( B +e C ) ) e. RR* ) -> ( -e ( ( A +e B ) +e C ) = -e ( A +e ( B +e C ) ) <-> ( ( A +e B ) +e C ) = ( A +e ( B +e C ) ) ) )
54	50, 52, 53	syl2anc 411	. 2 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( -e ( ( A +e B ) +e C ) = -e ( A +e ( B +e C ) ) <-> ( ( A +e B ) +e C ) = ( A +e ( B +e C ) ) ) )
55	48, 54	mpbid 147	1 |- ( ( ( A e. RR* /\ A =/= +oo ) /\ ( B e. RR* /\ B =/= +oo ) /\ ( C e. RR* /\ C =/= +oo ) ) -> ( ( A +e B ) +e C ) = ( A +e ( B +e C ) ) )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   /\ w3a 978   = wceq 1353   e. wcel 2148   =/= wne 2347  (class class class)co 5877   +oocpnf 7991   -oocmnf 7992   RR*cxr 7993   -ecxne 9771   +ecxad 9772

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 614  ax-in2 615  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-13 2150  ax-14 2151  ax-ext 2159  ax-sep 4123  ax-pow 4176  ax-pr 4211  ax-un 4435  ax-setind 4538  ax-cnex 7904  ax-resscn 7905  ax-1cn 7906  ax-1re 7907  ax-icn 7908  ax-addcl 7909  ax-addrcl 7910  ax-mulcl 7911  ax-addcom 7913  ax-addass 7915  ax-distr 7917  ax-i2m1 7918  ax-0id 7921  ax-rnegex 7922  ax-cnre 7924

This theorem depends on definitions:  df-bi 117  df-dc 835  df-3or 979  df-3an 980  df-tru 1356  df-fal 1359  df-nf 1461  df-sb 1763  df-eu 2029  df-mo 2030  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ne 2348  df-nel 2443  df-ral 2460  df-rex 2461  df-reu 2462  df-rab 2464  df-v 2741  df-sbc 2965  df-csb 3060  df-dif 3133  df-un 3135  df-in 3137  df-ss 3144  df-if 3537  df-pw 3579  df-sn 3600  df-pr 3601  df-op 3603  df-uni 3812  df-iun 3890  df-br 4006  df-opab 4067  df-mpt 4068  df-id 4295  df-xp 4634  df-rel 4635  df-cnv 4636  df-co 4637  df-dm 4638  df-rn 4639  df-res 4640  df-ima 4641  df-iota 5180  df-fun 5220  df-fn 5221  df-f 5222  df-fv 5226  df-riota 5833  df-ov 5880  df-oprab 5881  df-mpo 5882  df-1st 6143  df-2nd 6144  df-pnf 7996  df-mnf 7997  df-xr 7998  df-sub 8132  df-neg 8133  df-xneg 9774  df-xadd 9775

This theorem is referenced by: (None)