| Step | Hyp | Ref | Expression | 
						
							| 1 |  | id |  |-  ( 0 || K -> 0 || K ) | 
						
							| 2 |  | breq1 |  |-  ( M = 0 -> ( M || K <-> 0 || K ) ) | 
						
							| 3 | 2 | adantl |  |-  ( ( N e. ZZ /\ M = 0 ) -> ( M || K <-> 0 || K ) ) | 
						
							| 4 |  | oveq1 |  |-  ( M = 0 -> ( M lcm N ) = ( 0 lcm N ) ) | 
						
							| 5 |  | 0z |  |-  0 e. ZZ | 
						
							| 6 |  | lcmcom |  |-  ( ( 0 e. ZZ /\ N e. ZZ ) -> ( 0 lcm N ) = ( N lcm 0 ) ) | 
						
							| 7 | 5 6 | mpan |  |-  ( N e. ZZ -> ( 0 lcm N ) = ( N lcm 0 ) ) | 
						
							| 8 |  | lcm0val |  |-  ( N e. ZZ -> ( N lcm 0 ) = 0 ) | 
						
							| 9 | 7 8 | eqtrd |  |-  ( N e. ZZ -> ( 0 lcm N ) = 0 ) | 
						
							| 10 | 4 9 | sylan9eqr |  |-  ( ( N e. ZZ /\ M = 0 ) -> ( M lcm N ) = 0 ) | 
						
							| 11 | 10 | breq1d |  |-  ( ( N e. ZZ /\ M = 0 ) -> ( ( M lcm N ) || K <-> 0 || K ) ) | 
						
							| 12 | 3 11 | imbi12d |  |-  ( ( N e. ZZ /\ M = 0 ) -> ( ( M || K -> ( M lcm N ) || K ) <-> ( 0 || K -> 0 || K ) ) ) | 
						
							| 13 | 1 12 | mpbiri |  |-  ( ( N e. ZZ /\ M = 0 ) -> ( M || K -> ( M lcm N ) || K ) ) | 
						
							| 14 | 13 | 3ad2antl3 |  |-  ( ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( M || K -> ( M lcm N ) || K ) ) | 
						
							| 15 | 14 | adantrd |  |-  ( ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 16 | 15 | ex |  |-  ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) -> ( M = 0 -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 17 |  | breq1 |  |-  ( N = 0 -> ( N || K <-> 0 || K ) ) | 
						
							| 18 | 17 | adantl |  |-  ( ( M e. ZZ /\ N = 0 ) -> ( N || K <-> 0 || K ) ) | 
						
							| 19 |  | oveq2 |  |-  ( N = 0 -> ( M lcm N ) = ( M lcm 0 ) ) | 
						
							| 20 |  | lcm0val |  |-  ( M e. ZZ -> ( M lcm 0 ) = 0 ) | 
						
							| 21 | 19 20 | sylan9eqr |  |-  ( ( M e. ZZ /\ N = 0 ) -> ( M lcm N ) = 0 ) | 
						
							| 22 | 21 | breq1d |  |-  ( ( M e. ZZ /\ N = 0 ) -> ( ( M lcm N ) || K <-> 0 || K ) ) | 
						
							| 23 | 18 22 | imbi12d |  |-  ( ( M e. ZZ /\ N = 0 ) -> ( ( N || K -> ( M lcm N ) || K ) <-> ( 0 || K -> 0 || K ) ) ) | 
						
							| 24 | 1 23 | mpbiri |  |-  ( ( M e. ZZ /\ N = 0 ) -> ( N || K -> ( M lcm N ) || K ) ) | 
						
							| 25 | 24 | 3ad2antl2 |  |-  ( ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( N || K -> ( M lcm N ) || K ) ) | 
						
							| 26 | 25 | adantld |  |-  ( ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 27 | 26 | ex |  |-  ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) -> ( N = 0 -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 28 |  | neanior |  |-  ( ( M =/= 0 /\ N =/= 0 ) <-> -. ( M = 0 \/ N = 0 ) ) | 
						
							| 29 |  | lcmcl |  |-  ( ( M e. ZZ /\ N e. ZZ ) -> ( M lcm N ) e. NN0 ) | 
						
							| 30 | 29 | nn0zd |  |-  ( ( M e. ZZ /\ N e. ZZ ) -> ( M lcm N ) e. ZZ ) | 
						
							| 31 |  | dvds0 |  |-  ( ( M lcm N ) e. ZZ -> ( M lcm N ) || 0 ) | 
						
							| 32 | 30 31 | syl |  |-  ( ( M e. ZZ /\ N e. ZZ ) -> ( M lcm N ) || 0 ) | 
						
							| 33 | 32 | a1d |  |-  ( ( M e. ZZ /\ N e. ZZ ) -> ( ( M || 0 /\ N || 0 ) -> ( M lcm N ) || 0 ) ) | 
						
							| 34 | 33 | adantr |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K = 0 ) -> ( ( M || 0 /\ N || 0 ) -> ( M lcm N ) || 0 ) ) | 
						
							| 35 |  | breq2 |  |-  ( K = 0 -> ( M || K <-> M || 0 ) ) | 
						
							| 36 |  | breq2 |  |-  ( K = 0 -> ( N || K <-> N || 0 ) ) | 
						
							| 37 | 35 36 | anbi12d |  |-  ( K = 0 -> ( ( M || K /\ N || K ) <-> ( M || 0 /\ N || 0 ) ) ) | 
						
							| 38 |  | breq2 |  |-  ( K = 0 -> ( ( M lcm N ) || K <-> ( M lcm N ) || 0 ) ) | 
						
							| 39 | 37 38 | imbi12d |  |-  ( K = 0 -> ( ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) <-> ( ( M || 0 /\ N || 0 ) -> ( M lcm N ) || 0 ) ) ) | 
						
							| 40 | 39 | adantl |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K = 0 ) -> ( ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) <-> ( ( M || 0 /\ N || 0 ) -> ( M lcm N ) || 0 ) ) ) | 
						
							| 41 | 34 40 | mpbird |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K = 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 42 | 41 | adantrl |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ ( K e. ZZ /\ K = 0 ) ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 43 | 42 | adantllr |  |-  ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ N e. ZZ ) /\ ( K e. ZZ /\ K = 0 ) ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 44 | 43 | adantlrr |  |-  ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) /\ ( K e. ZZ /\ K = 0 ) ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 45 | 44 | anassrs |  |-  ( ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) /\ K e. ZZ ) /\ K = 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 46 |  | nnabscl |  |-  ( ( M e. ZZ /\ M =/= 0 ) -> ( abs ` M ) e. NN ) | 
						
							| 47 |  | nnabscl |  |-  ( ( N e. ZZ /\ N =/= 0 ) -> ( abs ` N ) e. NN ) | 
						
							| 48 |  | nnabscl |  |-  ( ( K e. ZZ /\ K =/= 0 ) -> ( abs ` K ) e. NN ) | 
						
							| 49 |  | lcmgcdlem |  |-  ( ( ( abs ` M ) e. NN /\ ( abs ` N ) e. NN ) -> ( ( ( ( abs ` M ) lcm ( abs ` N ) ) x. ( ( abs ` M ) gcd ( abs ` N ) ) ) = ( abs ` ( ( abs ` M ) x. ( abs ` N ) ) ) /\ ( ( ( abs ` K ) e. NN /\ ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) ) ) | 
						
							| 50 | 49 | simprd |  |-  ( ( ( abs ` M ) e. NN /\ ( abs ` N ) e. NN ) -> ( ( ( abs ` K ) e. NN /\ ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) ) | 
						
							| 51 | 48 50 | sylani |  |-  ( ( ( abs ` M ) e. NN /\ ( abs ` N ) e. NN ) -> ( ( ( K e. ZZ /\ K =/= 0 ) /\ ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) ) | 
						
							| 52 | 46 47 51 | syl2an |  |-  ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) -> ( ( ( K e. ZZ /\ K =/= 0 ) /\ ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) ) | 
						
							| 53 | 52 | expdimp |  |-  ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) /\ ( K e. ZZ /\ K =/= 0 ) ) -> ( ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) ) | 
						
							| 54 |  | dvdsabsb |  |-  ( ( M e. ZZ /\ K e. ZZ ) -> ( M || K <-> M || ( abs ` K ) ) ) | 
						
							| 55 |  | zabscl |  |-  ( K e. ZZ -> ( abs ` K ) e. ZZ ) | 
						
							| 56 |  | absdvdsb |  |-  ( ( M e. ZZ /\ ( abs ` K ) e. ZZ ) -> ( M || ( abs ` K ) <-> ( abs ` M ) || ( abs ` K ) ) ) | 
						
							| 57 | 55 56 | sylan2 |  |-  ( ( M e. ZZ /\ K e. ZZ ) -> ( M || ( abs ` K ) <-> ( abs ` M ) || ( abs ` K ) ) ) | 
						
							| 58 | 54 57 | bitrd |  |-  ( ( M e. ZZ /\ K e. ZZ ) -> ( M || K <-> ( abs ` M ) || ( abs ` K ) ) ) | 
						
							| 59 | 58 | adantlr |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( M || K <-> ( abs ` M ) || ( abs ` K ) ) ) | 
						
							| 60 |  | dvdsabsb |  |-  ( ( N e. ZZ /\ K e. ZZ ) -> ( N || K <-> N || ( abs ` K ) ) ) | 
						
							| 61 |  | absdvdsb |  |-  ( ( N e. ZZ /\ ( abs ` K ) e. ZZ ) -> ( N || ( abs ` K ) <-> ( abs ` N ) || ( abs ` K ) ) ) | 
						
							| 62 | 55 61 | sylan2 |  |-  ( ( N e. ZZ /\ K e. ZZ ) -> ( N || ( abs ` K ) <-> ( abs ` N ) || ( abs ` K ) ) ) | 
						
							| 63 | 60 62 | bitrd |  |-  ( ( N e. ZZ /\ K e. ZZ ) -> ( N || K <-> ( abs ` N ) || ( abs ` K ) ) ) | 
						
							| 64 | 63 | adantll |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( N || K <-> ( abs ` N ) || ( abs ` K ) ) ) | 
						
							| 65 | 59 64 | anbi12d |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( ( M || K /\ N || K ) <-> ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) ) ) | 
						
							| 66 | 65 | bicomd |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) <-> ( M || K /\ N || K ) ) ) | 
						
							| 67 |  | lcmabs |  |-  ( ( M e. ZZ /\ N e. ZZ ) -> ( ( abs ` M ) lcm ( abs ` N ) ) = ( M lcm N ) ) | 
						
							| 68 | 67 | breq1d |  |-  ( ( M e. ZZ /\ N e. ZZ ) -> ( ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) <-> ( M lcm N ) || ( abs ` K ) ) ) | 
						
							| 69 | 68 | adantr |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) <-> ( M lcm N ) || ( abs ` K ) ) ) | 
						
							| 70 |  | dvdsabsb |  |-  ( ( ( M lcm N ) e. ZZ /\ K e. ZZ ) -> ( ( M lcm N ) || K <-> ( M lcm N ) || ( abs ` K ) ) ) | 
						
							| 71 | 30 70 | sylan |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( ( M lcm N ) || K <-> ( M lcm N ) || ( abs ` K ) ) ) | 
						
							| 72 | 69 71 | bitr4d |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) <-> ( M lcm N ) || K ) ) | 
						
							| 73 | 66 72 | imbi12d |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( ( ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) <-> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 74 | 73 | adantrr |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ ( K e. ZZ /\ K =/= 0 ) ) -> ( ( ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) <-> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 75 | 74 | adantllr |  |-  ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ N e. ZZ ) /\ ( K e. ZZ /\ K =/= 0 ) ) -> ( ( ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) <-> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 76 | 75 | adantlrr |  |-  ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) /\ ( K e. ZZ /\ K =/= 0 ) ) -> ( ( ( ( abs ` M ) || ( abs ` K ) /\ ( abs ` N ) || ( abs ` K ) ) -> ( ( abs ` M ) lcm ( abs ` N ) ) || ( abs ` K ) ) <-> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 77 | 53 76 | mpbid |  |-  ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) /\ ( K e. ZZ /\ K =/= 0 ) ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 78 | 77 | anassrs |  |-  ( ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) /\ K e. ZZ ) /\ K =/= 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 79 | 45 78 | pm2.61dane |  |-  ( ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) /\ K e. ZZ ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) | 
						
							| 80 | 79 | ex |  |-  ( ( ( M e. ZZ /\ M =/= 0 ) /\ ( N e. ZZ /\ N =/= 0 ) ) -> ( K e. ZZ -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 81 | 80 | an4s |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ ( M =/= 0 /\ N =/= 0 ) ) -> ( K e. ZZ -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 82 | 28 81 | sylan2br |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ -. ( M = 0 \/ N = 0 ) ) -> ( K e. ZZ -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 83 | 82 | impancom |  |-  ( ( ( M e. ZZ /\ N e. ZZ ) /\ K e. ZZ ) -> ( -. ( M = 0 \/ N = 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 84 | 83 | 3impa |  |-  ( ( M e. ZZ /\ N e. ZZ /\ K e. ZZ ) -> ( -. ( M = 0 \/ N = 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 85 | 84 | 3comr |  |-  ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) -> ( -. ( M = 0 \/ N = 0 ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) ) | 
						
							| 86 | 16 27 85 | ecase3d |  |-  ( ( K e. ZZ /\ M e. ZZ /\ N e. ZZ ) -> ( ( M || K /\ N || K ) -> ( M lcm N ) || K ) ) |