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Theorem lcmftp 15349
Description: The least common multiple of a triple of integers is the least common multiple of the third integer and the the least common multiple of the first two integers. Although there would be a shorter proof using lcmfunsn 15357, this explicit proof (not based on induction) should be kept. (Proof modification is discouraged.) (Contributed by AV, 23-Aug-2020.)
Assertion
Ref Expression
lcmftp  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (lcm `  { A ,  B ,  C } )  =  ( ( A lcm  B
) lcm  C ) )

Proof of Theorem lcmftp
Dummy variables  k  m are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 0z 11388 . . . . . . 7  |-  0  e.  ZZ
2 eltpg 4227 . . . . . . 7  |-  ( 0  e.  ZZ  ->  (
0  e.  { A ,  B ,  C }  <->  ( 0  =  A  \/  0  =  B  \/  0  =  C )
) )
31, 2ax-mp 5 . . . . . 6  |-  ( 0  e.  { A ,  B ,  C }  <->  ( 0  =  A  \/  0  =  B  \/  0  =  C )
)
43biimpri 218 . . . . 5  |-  ( ( 0  =  A  \/  0  =  B  \/  0  =  C )  ->  0  e.  { A ,  B ,  C }
)
5 tpssi 4369 . . . . 5  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  { A ,  B ,  C }  C_  ZZ )
64, 5anim12ci 591 . . . 4  |-  ( ( ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( { A ,  B ,  C }  C_  ZZ  /\  0  e. 
{ A ,  B ,  C } ) )
7 lcmf0val 15335 . . . 4  |-  ( ( { A ,  B ,  C }  C_  ZZ  /\  0  e.  { A ,  B ,  C }
)  ->  (lcm `  { A ,  B ,  C } )  =  0 )
86, 7syl 17 . . 3  |-  ( ( ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
(lcm `  { A ,  B ,  C }
)  =  0 )
9 0zd 11389 . . . . . . . . . 10  |-  ( C  e.  ZZ  ->  0  e.  ZZ )
10 lcmcom 15306 . . . . . . . . . 10  |-  ( ( 0  e.  ZZ  /\  C  e.  ZZ )  ->  ( 0 lcm  C )  =  ( C lcm  0
) )
119, 10mpancom 703 . . . . . . . . 9  |-  ( C  e.  ZZ  ->  (
0 lcm  C )  =  ( C lcm  0 ) )
12 lcm0val 15307 . . . . . . . . 9  |-  ( C  e.  ZZ  ->  ( C lcm  0 )  =  0 )
1311, 12eqtrd 2656 . . . . . . . 8  |-  ( C  e.  ZZ  ->  (
0 lcm  C )  =  0 )
1413eqcomd 2628 . . . . . . 7  |-  ( C  e.  ZZ  ->  0  =  ( 0 lcm  C
) )
15143ad2ant3 1084 . . . . . 6  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  0  =  ( 0 lcm  C
) )
1615adantl 482 . . . . 5  |-  ( ( 0  =  A  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  0  =  ( 0 lcm  C )
)
17 0zd 11389 . . . . . . . . . . 11  |-  ( B  e.  ZZ  ->  0  e.  ZZ )
18 lcmcom 15306 . . . . . . . . . . 11  |-  ( ( 0  e.  ZZ  /\  B  e.  ZZ )  ->  ( 0 lcm  B )  =  ( B lcm  0
) )
1917, 18mpancom 703 . . . . . . . . . 10  |-  ( B  e.  ZZ  ->  (
0 lcm  B )  =  ( B lcm  0 ) )
20 lcm0val 15307 . . . . . . . . . 10  |-  ( B  e.  ZZ  ->  ( B lcm  0 )  =  0 )
2119, 20eqtrd 2656 . . . . . . . . 9  |-  ( B  e.  ZZ  ->  (
0 lcm  B )  =  0 )
2221eqcomd 2628 . . . . . . . 8  |-  ( B  e.  ZZ  ->  0  =  ( 0 lcm  B
) )
23223ad2ant2 1083 . . . . . . 7  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  0  =  ( 0 lcm  B
) )
2423adantl 482 . . . . . 6  |-  ( ( 0  =  A  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  0  =  ( 0 lcm  B )
)
2524oveq1d 6665 . . . . 5  |-  ( ( 0  =  A  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  ( 0 lcm 
C )  =  ( ( 0 lcm  B ) lcm 
C ) )
26 oveq1 6657 . . . . . . 7  |-  ( 0  =  A  ->  (
0 lcm  B )  =  ( A lcm  B ) )
2726oveq1d 6665 . . . . . 6  |-  ( 0  =  A  ->  (
( 0 lcm  B ) lcm 
C )  =  ( ( A lcm  B ) lcm 
C ) )
2827adantr 481 . . . . 5  |-  ( ( 0  =  A  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  ( (
0 lcm  B ) lcm  C
)  =  ( ( A lcm  B ) lcm  C
) )
2916, 25, 283eqtrd 2660 . . . 4  |-  ( ( 0  =  A  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  0  =  ( ( A lcm  B
) lcm  C ) )
30 lcm0val 15307 . . . . . . . . 9  |-  ( A  e.  ZZ  ->  ( A lcm  0 )  =  0 )
3130eqcomd 2628 . . . . . . . 8  |-  ( A  e.  ZZ  ->  0  =  ( A lcm  0
) )
32313ad2ant1 1082 . . . . . . 7  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  0  =  ( A lcm  0
) )
3332adantl 482 . . . . . 6  |-  ( ( 0  =  B  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  0  =  ( A lcm  0 )
)
3433oveq1d 6665 . . . . 5  |-  ( ( 0  =  B  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  ( 0 lcm 
C )  =  ( ( A lcm  0 ) lcm 
C ) )
35133ad2ant3 1084 . . . . . 6  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
0 lcm  C )  =  0 )
3635adantl 482 . . . . 5  |-  ( ( 0  =  B  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  ( 0 lcm 
C )  =  0 )
37 oveq2 6658 . . . . . . 7  |-  ( 0  =  B  ->  ( A lcm  0 )  =  ( A lcm  B ) )
3837adantr 481 . . . . . 6  |-  ( ( 0  =  B  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  ( A lcm  0 )  =  ( A lcm  B ) )
3938oveq1d 6665 . . . . 5  |-  ( ( 0  =  B  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  ( ( A lcm  0 ) lcm  C )  =  ( ( A lcm 
B ) lcm  C ) )
4034, 36, 393eqtr3d 2664 . . . 4  |-  ( ( 0  =  B  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  0  =  ( ( A lcm  B
) lcm  C ) )
41 lcmcl 15314 . . . . . . . 8  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ )  ->  ( A lcm  B )  e.  NN0 )
4241nn0zd 11480 . . . . . . 7  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ )  ->  ( A lcm  B )  e.  ZZ )
43 lcm0val 15307 . . . . . . . 8  |-  ( ( A lcm  B )  e.  ZZ  ->  ( ( A lcm  B ) lcm  0 )  =  0 )
4443eqcomd 2628 . . . . . . 7  |-  ( ( A lcm  B )  e.  ZZ  ->  0  =  ( ( A lcm  B
) lcm  0 ) )
4542, 44syl 17 . . . . . 6  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ )  ->  0  =  ( ( A lcm  B ) lcm  0 ) )
46453adant3 1081 . . . . 5  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  0  =  ( ( A lcm 
B ) lcm  0 ) )
47 oveq2 6658 . . . . 5  |-  ( 0  =  C  ->  (
( A lcm  B ) lcm  0 )  =  ( ( A lcm  B ) lcm 
C ) )
4846, 47sylan9eqr 2678 . . . 4  |-  ( ( 0  =  C  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  0  =  ( ( A lcm  B
) lcm  C ) )
4929, 40, 483jaoian 1393 . . 3  |-  ( ( ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
0  =  ( ( A lcm  B ) lcm  C
) )
508, 49eqtrd 2656 . 2  |-  ( ( ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
(lcm `  { A ,  B ,  C }
)  =  ( ( A lcm  B ) lcm  C
) )
51423adant3 1081 . . . . . . . . . 10  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( A lcm  B )  e.  ZZ )
52 simp3 1063 . . . . . . . . . 10  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  C  e.  ZZ )
5351, 52jca 554 . . . . . . . . 9  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B )  e.  ZZ  /\  C  e.  ZZ ) )
5453adantl 482 . . . . . . . 8  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A lcm  B
)  e.  ZZ  /\  C  e.  ZZ )
)
55 dvdslcm 15311 . . . . . . . 8  |-  ( ( ( A lcm  B )  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C )  /\  C  ||  (
( A lcm  B ) lcm 
C ) ) )
5654, 55syl 17 . . . . . . 7  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A lcm  B
)  ||  ( ( A lcm  B ) lcm  C )  /\  C  ||  (
( A lcm  B ) lcm 
C ) ) )
57 dvdslcm 15311 . . . . . . . . . . . . . 14  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ )  ->  ( A  ||  ( A lcm  B )  /\  B  ||  ( A lcm  B ) ) )
58573adant3 1081 . . . . . . . . . . . . 13  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( A  ||  ( A lcm  B
)  /\  B  ||  ( A lcm  B ) ) )
59 simp1 1061 . . . . . . . . . . . . . . . . . 18  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  A  e.  ZZ )
60 lcmcl 15314 . . . . . . . . . . . . . . . . . . . 20  |-  ( ( ( A lcm  B )  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B ) lcm 
C )  e.  NN0 )
6153, 60syl 17 . . . . . . . . . . . . . . . . . . 19  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B ) lcm 
C )  e.  NN0 )
6261nn0zd 11480 . . . . . . . . . . . . . . . . . 18  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B ) lcm 
C )  e.  ZZ )
6359, 51, 623jca 1242 . . . . . . . . . . . . . . . . 17  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( A  e.  ZZ  /\  ( A lcm  B )  e.  ZZ  /\  ( ( A lcm  B
) lcm  C )  e.  ZZ ) )
64 dvdstr 15018 . . . . . . . . . . . . . . . . 17  |-  ( ( A  e.  ZZ  /\  ( A lcm  B )  e.  ZZ  /\  ( ( A lcm  B ) lcm  C
)  e.  ZZ )  ->  ( ( A 
||  ( A lcm  B
)  /\  ( A lcm  B )  ||  ( ( A lcm  B ) lcm  C
) )  ->  A  ||  ( ( A lcm  B
) lcm  C ) ) )
6563, 64syl 17 . . . . . . . . . . . . . . . 16  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A  ||  ( A lcm  B )  /\  ( A lcm  B )  ||  (
( A lcm  B ) lcm 
C ) )  ->  A  ||  ( ( A lcm 
B ) lcm  C ) ) )
6665expd 452 . . . . . . . . . . . . . . 15  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( A  ||  ( A lcm  B
)  ->  ( ( A lcm  B )  ||  (
( A lcm  B ) lcm 
C )  ->  A  ||  ( ( A lcm  B
) lcm  C ) ) ) )
6766com12 32 . . . . . . . . . . . . . 14  |-  ( A 
||  ( A lcm  B
)  ->  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C )  ->  A  ||  (
( A lcm  B ) lcm 
C ) ) ) )
6867adantr 481 . . . . . . . . . . . . 13  |-  ( ( A  ||  ( A lcm 
B )  /\  B  ||  ( A lcm  B ) )  ->  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C )  ->  A  ||  (
( A lcm  B ) lcm 
C ) ) ) )
6958, 68mpcom 38 . . . . . . . . . . . 12  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C )  ->  A  ||  (
( A lcm  B ) lcm 
C ) ) )
7069adantl 482 . . . . . . . . . . 11  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A lcm  B
)  ||  ( ( A lcm  B ) lcm  C )  ->  A  ||  (
( A lcm  B ) lcm 
C ) ) )
7170com12 32 . . . . . . . . . 10  |-  ( ( A lcm  B )  ||  ( ( A lcm  B
) lcm  C )  -> 
( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  A  ||  (
( A lcm  B ) lcm 
C ) ) )
7271adantr 481 . . . . . . . . 9  |-  ( ( ( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C )  /\  C  ||  (
( A lcm  B ) lcm 
C ) )  -> 
( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  A  ||  (
( A lcm  B ) lcm 
C ) ) )
7372impcom 446 . . . . . . . 8  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  ( ( A lcm  B )  ||  (
( A lcm  B ) lcm 
C )  /\  C  ||  ( ( A lcm  B
) lcm  C ) ) )  ->  A  ||  (
( A lcm  B ) lcm 
C ) )
74 simpr 477 . . . . . . . . . . . . . . 15  |-  ( ( A  ||  ( A lcm 
B )  /\  B  ||  ( A lcm  B ) )  ->  B  ||  ( A lcm  B ) )
7557, 74syl 17 . . . . . . . . . . . . . 14  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ )  ->  B  ||  ( A lcm 
B ) )
76753adant3 1081 . . . . . . . . . . . . 13  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  B  ||  ( A lcm  B ) )
7776adantl 482 . . . . . . . . . . . 12  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  B  ||  ( A lcm  B
) )
78 simp2 1062 . . . . . . . . . . . . . . 15  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  B  e.  ZZ )
7978, 51, 623jca 1242 . . . . . . . . . . . . . 14  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( B  e.  ZZ  /\  ( A lcm  B )  e.  ZZ  /\  ( ( A lcm  B
) lcm  C )  e.  ZZ ) )
8079adantl 482 . . . . . . . . . . . . 13  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( B  e.  ZZ  /\  ( A lcm  B )  e.  ZZ  /\  (
( A lcm  B ) lcm 
C )  e.  ZZ ) )
81 dvdstr 15018 . . . . . . . . . . . . 13  |-  ( ( B  e.  ZZ  /\  ( A lcm  B )  e.  ZZ  /\  ( ( A lcm  B ) lcm  C
)  e.  ZZ )  ->  ( ( B 
||  ( A lcm  B
)  /\  ( A lcm  B )  ||  ( ( A lcm  B ) lcm  C
) )  ->  B  ||  ( ( A lcm  B
) lcm  C ) ) )
8280, 81syl 17 . . . . . . . . . . . 12  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( B  ||  ( A lcm  B )  /\  ( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C ) )  ->  B  ||  (
( A lcm  B ) lcm 
C ) ) )
8377, 82mpand 711 . . . . . . . . . . 11  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A lcm  B
)  ||  ( ( A lcm  B ) lcm  C )  ->  B  ||  (
( A lcm  B ) lcm 
C ) ) )
8483com12 32 . . . . . . . . . 10  |-  ( ( A lcm  B )  ||  ( ( A lcm  B
) lcm  C )  -> 
( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  B  ||  (
( A lcm  B ) lcm 
C ) ) )
8584adantr 481 . . . . . . . . 9  |-  ( ( ( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C )  /\  C  ||  (
( A lcm  B ) lcm 
C ) )  -> 
( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  ->  B  ||  (
( A lcm  B ) lcm 
C ) ) )
8685impcom 446 . . . . . . . 8  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  ( ( A lcm  B )  ||  (
( A lcm  B ) lcm 
C )  /\  C  ||  ( ( A lcm  B
) lcm  C ) ) )  ->  B  ||  (
( A lcm  B ) lcm 
C ) )
87 simpr 477 . . . . . . . . 9  |-  ( ( ( A lcm  B ) 
||  ( ( A lcm 
B ) lcm  C )  /\  C  ||  (
( A lcm  B ) lcm 
C ) )  ->  C  ||  ( ( A lcm 
B ) lcm  C ) )
8887adantl 482 . . . . . . . 8  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  ( ( A lcm  B )  ||  (
( A lcm  B ) lcm 
C )  /\  C  ||  ( ( A lcm  B
) lcm  C ) ) )  ->  C  ||  (
( A lcm  B ) lcm 
C ) )
8973, 86, 883jca 1242 . . . . . . 7  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  ( ( A lcm  B )  ||  (
( A lcm  B ) lcm 
C )  /\  C  ||  ( ( A lcm  B
) lcm  C ) ) )  ->  ( A  ||  ( ( A lcm  B
) lcm  C )  /\  B  ||  ( ( A lcm 
B ) lcm  C )  /\  C  ||  (
( A lcm  B ) lcm 
C ) ) )
9056, 89mpdan 702 . . . . . 6  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( A  ||  (
( A lcm  B ) lcm 
C )  /\  B  ||  ( ( A lcm  B
) lcm  C )  /\  C  ||  ( ( A lcm 
B ) lcm  C ) ) )
91 breq1 4656 . . . . . . . 8  |-  ( m  =  A  ->  (
m  ||  ( ( A lcm  B ) lcm  C )  <-> 
A  ||  ( ( A lcm  B ) lcm  C ) ) )
92 breq1 4656 . . . . . . . 8  |-  ( m  =  B  ->  (
m  ||  ( ( A lcm  B ) lcm  C )  <-> 
B  ||  ( ( A lcm  B ) lcm  C ) ) )
93 breq1 4656 . . . . . . . 8  |-  ( m  =  C  ->  (
m  ||  ( ( A lcm  B ) lcm  C )  <-> 
C  ||  ( ( A lcm  B ) lcm  C ) ) )
9491, 92, 93raltpg 4236 . . . . . . 7  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( A. m  e.  { A ,  B ,  C }
m  ||  ( ( A lcm  B ) lcm  C )  <-> 
( A  ||  (
( A lcm  B ) lcm 
C )  /\  B  ||  ( ( A lcm  B
) lcm  C )  /\  C  ||  ( ( A lcm 
B ) lcm  C ) ) ) )
9594adantl 482 . . . . . 6  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( A. m  e. 
{ A ,  B ,  C } m  ||  ( ( A lcm  B
) lcm  C )  <->  ( A  ||  ( ( A lcm  B
) lcm  C )  /\  B  ||  ( ( A lcm 
B ) lcm  C )  /\  C  ||  (
( A lcm  B ) lcm 
C ) ) ) )
9690, 95mpbird 247 . . . . 5  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  A. m  e.  { A ,  B ,  C }
m  ||  ( ( A lcm  B ) lcm  C ) )
97 breq1 4656 . . . . . . . . 9  |-  ( m  =  A  ->  (
m  ||  k  <->  A  ||  k
) )
98 breq1 4656 . . . . . . . . 9  |-  ( m  =  B  ->  (
m  ||  k  <->  B  ||  k
) )
99 breq1 4656 . . . . . . . . 9  |-  ( m  =  C  ->  (
m  ||  k  <->  C  ||  k
) )
10097, 98, 99raltpg 4236 . . . . . . . 8  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( A. m  e.  { A ,  B ,  C }
m  ||  k  <->  ( A  ||  k  /\  B  ||  k  /\  C  ||  k
) ) )
101100ad2antlr 763 . . . . . . 7  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( A. m  e.  { A ,  B ,  C }
m  ||  k  <->  ( A  ||  k  /\  B  ||  k  /\  C  ||  k
) ) )
102 simpr 477 . . . . . . . . . . 11  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  k  e.  NN )
10351ad2antlr 763 . . . . . . . . . . 11  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( A lcm 
B )  e.  ZZ )
10452ad2antlr 763 . . . . . . . . . . 11  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  C  e.  ZZ )
105102, 103, 1043jca 1242 . . . . . . . . . 10  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( k  e.  NN  /\  ( A lcm  B )  e.  ZZ  /\  C  e.  ZZ ) )
106105adantr 481 . . . . . . . . 9  |-  ( ( ( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  /\  ( A  ||  k  /\  B  ||  k  /\  C  ||  k ) )  -> 
( k  e.  NN  /\  ( A lcm  B )  e.  ZZ  /\  C  e.  ZZ ) )
107 3ioran 1056 . . . . . . . . . . . . . . . . 17  |-  ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  <->  ( -.  0  =  A  /\  -.  0  =  B  /\  -.  0  =  C ) )
108 eqcom 2629 . . . . . . . . . . . . . . . . . . . . . 22  |-  ( 0  =  A  <->  A  = 
0 )
109108notbii 310 . . . . . . . . . . . . . . . . . . . . 21  |-  ( -.  0  =  A  <->  -.  A  =  0 )
110 eqcom 2629 . . . . . . . . . . . . . . . . . . . . . 22  |-  ( 0  =  B  <->  B  = 
0 )
111110notbii 310 . . . . . . . . . . . . . . . . . . . . 21  |-  ( -.  0  =  B  <->  -.  B  =  0 )
112109, 111anbi12i 733 . . . . . . . . . . . . . . . . . . . 20  |-  ( ( -.  0  =  A  /\  -.  0  =  B )  <->  ( -.  A  =  0  /\  -.  B  =  0
) )
113112biimpi 206 . . . . . . . . . . . . . . . . . . 19  |-  ( ( -.  0  =  A  /\  -.  0  =  B )  ->  ( -.  A  =  0  /\  -.  B  =  0 ) )
114 ioran 511 . . . . . . . . . . . . . . . . . . 19  |-  ( -.  ( A  =  0  \/  B  =  0 )  <->  ( -.  A  =  0  /\  -.  B  =  0 ) )
115113, 114sylibr 224 . . . . . . . . . . . . . . . . . 18  |-  ( ( -.  0  =  A  /\  -.  0  =  B )  ->  -.  ( A  =  0  \/  B  =  0
) )
1161153adant3 1081 . . . . . . . . . . . . . . . . 17  |-  ( ( -.  0  =  A  /\  -.  0  =  B  /\  -.  0  =  C )  ->  -.  ( A  =  0  \/  B  =  0
) )
117107, 116sylbi 207 . . . . . . . . . . . . . . . 16  |-  ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  ->  -.  ( A  =  0  \/  B  =  0 ) )
118 id 22 . . . . . . . . . . . . . . . . 17  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ )  ->  ( A  e.  ZZ  /\  B  e.  ZZ ) )
1191183adant3 1081 . . . . . . . . . . . . . . . 16  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( A  e.  ZZ  /\  B  e.  ZZ ) )
120117, 119anim12ci 591 . . . . . . . . . . . . . . 15  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A  e.  ZZ  /\  B  e.  ZZ )  /\  -.  ( A  =  0  \/  B  =  0
) ) )
121 lcmn0cl 15310 . . . . . . . . . . . . . . 15  |-  ( ( ( A  e.  ZZ  /\  B  e.  ZZ )  /\  -.  ( A  =  0  \/  B  =  0 ) )  ->  ( A lcm  B
)  e.  NN )
122120, 121syl 17 . . . . . . . . . . . . . 14  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( A lcm  B )  e.  NN )
123 nnne0 11053 . . . . . . . . . . . . . . 15  |-  ( ( A lcm  B )  e.  NN  ->  ( A lcm  B )  =/=  0 )
124123neneqd 2799 . . . . . . . . . . . . . 14  |-  ( ( A lcm  B )  e.  NN  ->  -.  ( A lcm  B )  =  0 )
125122, 124syl 17 . . . . . . . . . . . . 13  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  -.  ( A lcm  B )  =  0 )
126 eqcom 2629 . . . . . . . . . . . . . . . . . 18  |-  ( 0  =  C  <->  C  = 
0 )
127126notbii 310 . . . . . . . . . . . . . . . . 17  |-  ( -.  0  =  C  <->  -.  C  =  0 )
128127biimpi 206 . . . . . . . . . . . . . . . 16  |-  ( -.  0  =  C  ->  -.  C  =  0
)
1291283ad2ant3 1084 . . . . . . . . . . . . . . 15  |-  ( ( -.  0  =  A  /\  -.  0  =  B  /\  -.  0  =  C )  ->  -.  C  =  0 )
130107, 129sylbi 207 . . . . . . . . . . . . . 14  |-  ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  ->  -.  C  =  0 )
131130adantr 481 . . . . . . . . . . . . 13  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  -.  C  =  0
)
132125, 131jca 554 . . . . . . . . . . . 12  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( -.  ( A lcm 
B )  =  0  /\  -.  C  =  0 ) )
133132adantr 481 . . . . . . . . . . 11  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( -.  ( A lcm  B )  =  0  /\  -.  C  =  0 ) )
134133adantr 481 . . . . . . . . . 10  |-  ( ( ( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  /\  ( A  ||  k  /\  B  ||  k  /\  C  ||  k ) )  -> 
( -.  ( A lcm 
B )  =  0  /\  -.  C  =  0 ) )
135 ioran 511 . . . . . . . . . 10  |-  ( -.  ( ( A lcm  B
)  =  0  \/  C  =  0 )  <-> 
( -.  ( A lcm 
B )  =  0  /\  -.  C  =  0 ) )
136134, 135sylibr 224 . . . . . . . . 9  |-  ( ( ( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  /\  ( A  ||  k  /\  B  ||  k  /\  C  ||  k ) )  ->  -.  ( ( A lcm  B
)  =  0  \/  C  =  0 ) )
137119adantl 482 . . . . . . . . . . . . . . 15  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( A  e.  ZZ  /\  B  e.  ZZ ) )
138 nnz 11399 . . . . . . . . . . . . . . 15  |-  ( k  e.  NN  ->  k  e.  ZZ )
139137, 138anim12ci 591 . . . . . . . . . . . . . 14  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( k  e.  ZZ  /\  ( A  e.  ZZ  /\  B  e.  ZZ ) ) )
140 3anass 1042 . . . . . . . . . . . . . 14  |-  ( ( k  e.  ZZ  /\  A  e.  ZZ  /\  B  e.  ZZ )  <->  ( k  e.  ZZ  /\  ( A  e.  ZZ  /\  B  e.  ZZ ) ) )
141139, 140sylibr 224 . . . . . . . . . . . . 13  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( k  e.  ZZ  /\  A  e.  ZZ  /\  B  e.  ZZ ) )
142 lcmdvds 15321 . . . . . . . . . . . . 13  |-  ( ( k  e.  ZZ  /\  A  e.  ZZ  /\  B  e.  ZZ )  ->  (
( A  ||  k  /\  B  ||  k )  ->  ( A lcm  B
)  ||  k )
)
143141, 142syl 17 . . . . . . . . . . . 12  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( ( A  ||  k  /\  B  ||  k )  -> 
( A lcm  B ) 
||  k ) )
144143com12 32 . . . . . . . . . . 11  |-  ( ( A  ||  k  /\  B  ||  k )  -> 
( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  /\  k  e.  NN )  ->  ( A lcm  B ) 
||  k ) )
1451443adant3 1081 . . . . . . . . . 10  |-  ( ( A  ||  k  /\  B  ||  k  /\  C  ||  k )  ->  (
( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( A lcm 
B )  ||  k
) )
146145impcom 446 . . . . . . . . 9  |-  ( ( ( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  /\  ( A  ||  k  /\  B  ||  k  /\  C  ||  k ) )  -> 
( A lcm  B ) 
||  k )
147 simp3 1063 . . . . . . . . . 10  |-  ( ( A  ||  k  /\  B  ||  k  /\  C  ||  k )  ->  C  ||  k )
148147adantl 482 . . . . . . . . 9  |-  ( ( ( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  /\  ( A  ||  k  /\  B  ||  k  /\  C  ||  k ) )  ->  C  ||  k )
149 lcmledvds 15312 . . . . . . . . . 10  |-  ( ( ( k  e.  NN  /\  ( A lcm  B )  e.  ZZ  /\  C  e.  ZZ )  /\  -.  ( ( A lcm  B
)  =  0  \/  C  =  0 ) )  ->  ( (
( A lcm  B ) 
||  k  /\  C  ||  k )  ->  (
( A lcm  B ) lcm 
C )  <_  k
) )
150149imp 445 . . . . . . . . 9  |-  ( ( ( ( k  e.  NN  /\  ( A lcm 
B )  e.  ZZ  /\  C  e.  ZZ )  /\  -.  ( ( A lcm  B )  =  0  \/  C  =  0 ) )  /\  ( ( A lcm  B
)  ||  k  /\  C  ||  k ) )  ->  ( ( A lcm 
B ) lcm  C )  <_  k )
151106, 136, 146, 148, 150syl22anc 1327 . . . . . . . 8  |-  ( ( ( ( -.  (
0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  /\  ( A  ||  k  /\  B  ||  k  /\  C  ||  k ) )  -> 
( ( A lcm  B
) lcm  C )  <_ 
k )
152151ex 450 . . . . . . 7  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( ( A  ||  k  /\  B  ||  k  /\  C  ||  k )  ->  (
( A lcm  B ) lcm 
C )  <_  k
) )
153101, 152sylbid 230 . . . . . 6  |-  ( ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )
)  /\  k  e.  NN )  ->  ( A. m  e.  { A ,  B ,  C }
m  ||  k  ->  ( ( A lcm  B ) lcm 
C )  <_  k
) )
154153ralrimiva 2966 . . . . 5  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  A. k  e.  NN  ( A. m  e.  { A ,  B ,  C } m  ||  k  ->  ( ( A lcm  B
) lcm  C )  <_ 
k ) )
15596, 154jca 554 . . . 4  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( A. m  e. 
{ A ,  B ,  C } m  ||  ( ( A lcm  B
) lcm  C )  /\  A. k  e.  NN  ( A. m  e.  { A ,  B ,  C }
m  ||  k  ->  ( ( A lcm  B ) lcm 
C )  <_  k
) ) )
156109biimpi 206 . . . . . . . . . . . . . . . 16  |-  ( -.  0  =  A  ->  -.  A  =  0
)
157111biimpi 206 . . . . . . . . . . . . . . . 16  |-  ( -.  0  =  B  ->  -.  B  =  0
)
158156, 157anim12i 590 . . . . . . . . . . . . . . 15  |-  ( ( -.  0  =  A  /\  -.  0  =  B )  ->  ( -.  A  =  0  /\  -.  B  =  0 ) )
159158, 114sylibr 224 . . . . . . . . . . . . . 14  |-  ( ( -.  0  =  A  /\  -.  0  =  B )  ->  -.  ( A  =  0  \/  B  =  0
) )
1601593adant3 1081 . . . . . . . . . . . . 13  |-  ( ( -.  0  =  A  /\  -.  0  =  B  /\  -.  0  =  C )  ->  -.  ( A  =  0  \/  B  =  0
) )
161107, 160sylbi 207 . . . . . . . . . . . 12  |-  ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  ->  -.  ( A  =  0  \/  B  =  0 ) )
162161, 119anim12ci 591 . . . . . . . . . . 11  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A  e.  ZZ  /\  B  e.  ZZ )  /\  -.  ( A  =  0  \/  B  =  0
) ) )
163162, 121syl 17 . . . . . . . . . 10  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( A lcm  B )  e.  NN )
164163, 124syl 17 . . . . . . . . 9  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  -.  ( A lcm  B )  =  0 )
165164, 131jca 554 . . . . . . . 8  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( -.  ( A lcm 
B )  =  0  /\  -.  C  =  0 ) )
166165, 135sylibr 224 . . . . . . 7  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  -.  ( ( A lcm  B
)  =  0  \/  C  =  0 ) )
16754, 166jca 554 . . . . . 6  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( ( A lcm 
B )  e.  ZZ  /\  C  e.  ZZ )  /\  -.  ( ( A lcm  B )  =  0  \/  C  =  0 ) ) )
168 lcmn0cl 15310 . . . . . 6  |-  ( ( ( ( A lcm  B
)  e.  ZZ  /\  C  e.  ZZ )  /\  -.  ( ( A lcm 
B )  =  0  \/  C  =  0 ) )  ->  (
( A lcm  B ) lcm 
C )  e.  NN )
169167, 168syl 17 . . . . 5  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A lcm  B
) lcm  C )  e.  NN )
1705adantl 482 . . . . 5  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  { A ,  B ,  C }  C_  ZZ )
171 tpfi 8236 . . . . . 6  |-  { A ,  B ,  C }  e.  Fin
172171a1i 11 . . . . 5  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  { A ,  B ,  C }  e.  Fin )
1733a1i 11 . . . . . . . . 9  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
0  e.  { A ,  B ,  C }  <->  ( 0  =  A  \/  0  =  B  \/  0  =  C )
) )
174173biimpd 219 . . . . . . . 8  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (
0  e.  { A ,  B ,  C }  ->  ( 0  =  A  \/  0  =  B  \/  0  =  C ) ) )
175174con3d 148 . . . . . . 7  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  ->  -.  0  e.  { A ,  B ,  C } ) )
176175impcom 446 . . . . . 6  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  ->  -.  0  e.  { A ,  B ,  C }
)
177 df-nel 2898 . . . . . 6  |-  ( 0  e/  { A ,  B ,  C }  <->  -.  0  e.  { A ,  B ,  C }
)
178176, 177sylibr 224 . . . . 5  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
0  e/  { A ,  B ,  C }
)
179 lcmf 15346 . . . . 5  |-  ( ( ( ( A lcm  B
) lcm  C )  e.  NN  /\  ( { A ,  B ,  C }  C_  ZZ  /\  { A ,  B ,  C }  e.  Fin  /\  0  e/  { A ,  B ,  C }
) )  ->  (
( ( A lcm  B
) lcm  C )  =  (lcm `  { A ,  B ,  C }
)  <->  ( A. m  e.  { A ,  B ,  C } m  ||  ( ( A lcm  B
) lcm  C )  /\  A. k  e.  NN  ( A. m  e.  { A ,  B ,  C }
m  ||  k  ->  ( ( A lcm  B ) lcm 
C )  <_  k
) ) ) )
180169, 170, 172, 178, 179syl13anc 1328 . . . 4  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( ( A lcm 
B ) lcm  C )  =  (lcm `  { A ,  B ,  C }
)  <->  ( A. m  e.  { A ,  B ,  C } m  ||  ( ( A lcm  B
) lcm  C )  /\  A. k  e.  NN  ( A. m  e.  { A ,  B ,  C }
m  ||  k  ->  ( ( A lcm  B ) lcm 
C )  <_  k
) ) ) )
181155, 180mpbird 247 . . 3  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
( ( A lcm  B
) lcm  C )  =  (lcm `  { A ,  B ,  C }
) )
182181eqcomd 2628 . 2  |-  ( ( -.  ( 0  =  A  \/  0  =  B  \/  0  =  C )  /\  ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ ) )  -> 
(lcm `  { A ,  B ,  C }
)  =  ( ( A lcm  B ) lcm  C
) )
18350, 182pm2.61ian 831 1  |-  ( ( A  e.  ZZ  /\  B  e.  ZZ  /\  C  e.  ZZ )  ->  (lcm `  { A ,  B ,  C } )  =  ( ( A lcm  B
) lcm  C ) )
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    -> wi 4    <-> wb 196    \/ wo 383    /\ wa 384    \/ w3o 1036    /\ w3a 1037    = wceq 1483    e. wcel 1990    e/ wnel 2897   A.wral 2912    C_ wss 3574   {ctp 4181   class class class wbr 4653   ` cfv 5888  (class class class)co 6650   Fincfn 7955   0cc0 9936    <_ cle 10075   NNcn 11020   NN0cn0 11292   ZZcz 11377    || cdvds 14983   lcm clcm 15301  lcmclcmf 15302
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-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-rep 4771  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949  ax-inf2 8538  ax-cnex 9992  ax-resscn 9993  ax-1cn 9994  ax-icn 9995  ax-addcl 9996  ax-addrcl 9997  ax-mulcl 9998  ax-mulrcl 9999  ax-mulcom 10000  ax-addass 10001  ax-mulass 10002  ax-distr 10003  ax-i2m1 10004  ax-1ne0 10005  ax-1rid 10006  ax-rnegex 10007  ax-rrecex 10008  ax-cnre 10009  ax-pre-lttri 10010  ax-pre-lttrn 10011  ax-pre-ltadd 10012  ax-pre-mulgt0 10013  ax-pre-sup 10014
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1038  df-3an 1039  df-tru 1486  df-fal 1489  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-nel 2898  df-ral 2917  df-rex 2918  df-reu 2919  df-rmo 2920  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-pss 3590  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-tp 4182  df-op 4184  df-uni 4437  df-int 4476  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-tr 4753  df-id 5024  df-eprel 5029  df-po 5035  df-so 5036  df-fr 5073  df-se 5074  df-we 5075  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-pred 5680  df-ord 5726  df-on 5727  df-lim 5728  df-suc 5729  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-isom 5897  df-riota 6611  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-om 7066  df-1st 7168  df-2nd 7169  df-wrecs 7407  df-recs 7468  df-rdg 7506  df-1o 7560  df-oadd 7564  df-er 7742  df-en 7956  df-dom 7957  df-sdom 7958  df-fin 7959  df-sup 8348  df-inf 8349  df-oi 8415  df-card 8765  df-pnf 10076  df-mnf 10077  df-xr 10078  df-ltxr 10079  df-le 10080  df-sub 10268  df-neg 10269  df-div 10685  df-nn 11021  df-2 11079  df-3 11080  df-n0 11293  df-z 11378  df-uz 11688  df-rp 11833  df-fz 12327  df-fzo 12466  df-fl 12593  df-mod 12669  df-seq 12802  df-exp 12861  df-hash 13118  df-cj 13839  df-re 13840  df-im 13841  df-sqrt 13975  df-abs 13976  df-clim 14219  df-prod 14636  df-dvds 14984  df-gcd 15217  df-lcm 15303  df-lcmf 15304
This theorem is referenced by:  lcmf2a3a4e12  15360
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