| Step | Hyp | Ref | Expression | 
						
							| 1 |  | oveq2 |  |-  ( x = N -> ( A /L x ) = ( A /L N ) ) | 
						
							| 2 | 1 | oveq1d |  |-  ( x = N -> ( ( A /L x ) x. ( A /L 0 ) ) = ( ( A /L N ) x. ( A /L 0 ) ) ) | 
						
							| 3 | 2 | eqeq2d |  |-  ( x = N -> ( ( A /L 0 ) = ( ( A /L x ) x. ( A /L 0 ) ) <-> ( A /L 0 ) = ( ( A /L N ) x. ( A /L 0 ) ) ) ) | 
						
							| 4 |  | sq1 |  |-  ( 1 ^ 2 ) = 1 | 
						
							| 5 | 4 | eqeq2i |  |-  ( ( A ^ 2 ) = ( 1 ^ 2 ) <-> ( A ^ 2 ) = 1 ) | 
						
							| 6 |  | nn0re |  |-  ( A e. NN0 -> A e. RR ) | 
						
							| 7 |  | nn0ge0 |  |-  ( A e. NN0 -> 0 <_ A ) | 
						
							| 8 |  | 1re |  |-  1 e. RR | 
						
							| 9 |  | 0le1 |  |-  0 <_ 1 | 
						
							| 10 |  | sq11 |  |-  ( ( ( A e. RR /\ 0 <_ A ) /\ ( 1 e. RR /\ 0 <_ 1 ) ) -> ( ( A ^ 2 ) = ( 1 ^ 2 ) <-> A = 1 ) ) | 
						
							| 11 | 8 9 10 | mpanr12 |  |-  ( ( A e. RR /\ 0 <_ A ) -> ( ( A ^ 2 ) = ( 1 ^ 2 ) <-> A = 1 ) ) | 
						
							| 12 | 6 7 11 | syl2anc |  |-  ( A e. NN0 -> ( ( A ^ 2 ) = ( 1 ^ 2 ) <-> A = 1 ) ) | 
						
							| 13 | 12 | adantr |  |-  ( ( A e. NN0 /\ x e. ZZ ) -> ( ( A ^ 2 ) = ( 1 ^ 2 ) <-> A = 1 ) ) | 
						
							| 14 | 5 13 | bitr3id |  |-  ( ( A e. NN0 /\ x e. ZZ ) -> ( ( A ^ 2 ) = 1 <-> A = 1 ) ) | 
						
							| 15 | 14 | biimpa |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> A = 1 ) | 
						
							| 16 | 15 | oveq1d |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( A /L x ) = ( 1 /L x ) ) | 
						
							| 17 |  | 1lgs |  |-  ( x e. ZZ -> ( 1 /L x ) = 1 ) | 
						
							| 18 | 17 | ad2antlr |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( 1 /L x ) = 1 ) | 
						
							| 19 | 16 18 | eqtrd |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( A /L x ) = 1 ) | 
						
							| 20 | 19 | oveq1d |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( ( A /L x ) x. ( A /L 0 ) ) = ( 1 x. ( A /L 0 ) ) ) | 
						
							| 21 |  | nn0z |  |-  ( A e. NN0 -> A e. ZZ ) | 
						
							| 22 | 21 | ad2antrr |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> A e. ZZ ) | 
						
							| 23 |  | 0z |  |-  0 e. ZZ | 
						
							| 24 |  | lgscl |  |-  ( ( A e. ZZ /\ 0 e. ZZ ) -> ( A /L 0 ) e. ZZ ) | 
						
							| 25 | 22 23 24 | sylancl |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( A /L 0 ) e. ZZ ) | 
						
							| 26 | 25 | zcnd |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( A /L 0 ) e. CC ) | 
						
							| 27 | 26 | mullidd |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( 1 x. ( A /L 0 ) ) = ( A /L 0 ) ) | 
						
							| 28 | 20 27 | eqtr2d |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) = 1 ) -> ( A /L 0 ) = ( ( A /L x ) x. ( A /L 0 ) ) ) | 
						
							| 29 |  | lgscl |  |-  ( ( A e. ZZ /\ x e. ZZ ) -> ( A /L x ) e. ZZ ) | 
						
							| 30 | 21 29 | sylan |  |-  ( ( A e. NN0 /\ x e. ZZ ) -> ( A /L x ) e. ZZ ) | 
						
							| 31 | 30 | zcnd |  |-  ( ( A e. NN0 /\ x e. ZZ ) -> ( A /L x ) e. CC ) | 
						
							| 32 | 31 | adantr |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) =/= 1 ) -> ( A /L x ) e. CC ) | 
						
							| 33 | 32 | mul01d |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) =/= 1 ) -> ( ( A /L x ) x. 0 ) = 0 ) | 
						
							| 34 | 21 | adantr |  |-  ( ( A e. NN0 /\ x e. ZZ ) -> A e. ZZ ) | 
						
							| 35 |  | lgs0 |  |-  ( A e. ZZ -> ( A /L 0 ) = if ( ( A ^ 2 ) = 1 , 1 , 0 ) ) | 
						
							| 36 | 34 35 | syl |  |-  ( ( A e. NN0 /\ x e. ZZ ) -> ( A /L 0 ) = if ( ( A ^ 2 ) = 1 , 1 , 0 ) ) | 
						
							| 37 |  | ifnefalse |  |-  ( ( A ^ 2 ) =/= 1 -> if ( ( A ^ 2 ) = 1 , 1 , 0 ) = 0 ) | 
						
							| 38 | 36 37 | sylan9eq |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) =/= 1 ) -> ( A /L 0 ) = 0 ) | 
						
							| 39 | 38 | oveq2d |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) =/= 1 ) -> ( ( A /L x ) x. ( A /L 0 ) ) = ( ( A /L x ) x. 0 ) ) | 
						
							| 40 | 33 39 38 | 3eqtr4rd |  |-  ( ( ( A e. NN0 /\ x e. ZZ ) /\ ( A ^ 2 ) =/= 1 ) -> ( A /L 0 ) = ( ( A /L x ) x. ( A /L 0 ) ) ) | 
						
							| 41 | 28 40 | pm2.61dane |  |-  ( ( A e. NN0 /\ x e. ZZ ) -> ( A /L 0 ) = ( ( A /L x ) x. ( A /L 0 ) ) ) | 
						
							| 42 | 41 | ralrimiva |  |-  ( A e. NN0 -> A. x e. ZZ ( A /L 0 ) = ( ( A /L x ) x. ( A /L 0 ) ) ) | 
						
							| 43 | 42 | 3ad2ant1 |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> A. x e. ZZ ( A /L 0 ) = ( ( A /L x ) x. ( A /L 0 ) ) ) | 
						
							| 44 |  | simp3 |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> N e. ZZ ) | 
						
							| 45 | 3 43 44 | rspcdva |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( A /L 0 ) = ( ( A /L N ) x. ( A /L 0 ) ) ) | 
						
							| 46 | 45 | adantr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( A /L 0 ) = ( ( A /L N ) x. ( A /L 0 ) ) ) | 
						
							| 47 | 21 | 3ad2ant1 |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> A e. ZZ ) | 
						
							| 48 | 47 23 24 | sylancl |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( A /L 0 ) e. ZZ ) | 
						
							| 49 | 48 | zcnd |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( A /L 0 ) e. CC ) | 
						
							| 50 | 49 | adantr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( A /L 0 ) e. CC ) | 
						
							| 51 |  | lgscl |  |-  ( ( A e. ZZ /\ N e. ZZ ) -> ( A /L N ) e. ZZ ) | 
						
							| 52 | 47 44 51 | syl2anc |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( A /L N ) e. ZZ ) | 
						
							| 53 | 52 | zcnd |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( A /L N ) e. CC ) | 
						
							| 54 | 53 | adantr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( A /L N ) e. CC ) | 
						
							| 55 | 50 54 | mulcomd |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( ( A /L 0 ) x. ( A /L N ) ) = ( ( A /L N ) x. ( A /L 0 ) ) ) | 
						
							| 56 | 46 55 | eqtr4d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( A /L 0 ) = ( ( A /L 0 ) x. ( A /L N ) ) ) | 
						
							| 57 |  | oveq1 |  |-  ( M = 0 -> ( M x. N ) = ( 0 x. N ) ) | 
						
							| 58 | 44 | zcnd |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> N e. CC ) | 
						
							| 59 | 58 | mul02d |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( 0 x. N ) = 0 ) | 
						
							| 60 | 57 59 | sylan9eqr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( M x. N ) = 0 ) | 
						
							| 61 | 60 | oveq2d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( A /L ( M x. N ) ) = ( A /L 0 ) ) | 
						
							| 62 |  | simpr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> M = 0 ) | 
						
							| 63 | 62 | oveq2d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( A /L M ) = ( A /L 0 ) ) | 
						
							| 64 | 63 | oveq1d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( ( A /L M ) x. ( A /L N ) ) = ( ( A /L 0 ) x. ( A /L N ) ) ) | 
						
							| 65 | 56 61 64 | 3eqtr4d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ M = 0 ) -> ( A /L ( M x. N ) ) = ( ( A /L M ) x. ( A /L N ) ) ) | 
						
							| 66 |  | oveq2 |  |-  ( x = M -> ( A /L x ) = ( A /L M ) ) | 
						
							| 67 | 66 | oveq1d |  |-  ( x = M -> ( ( A /L x ) x. ( A /L 0 ) ) = ( ( A /L M ) x. ( A /L 0 ) ) ) | 
						
							| 68 | 67 | eqeq2d |  |-  ( x = M -> ( ( A /L 0 ) = ( ( A /L x ) x. ( A /L 0 ) ) <-> ( A /L 0 ) = ( ( A /L M ) x. ( A /L 0 ) ) ) ) | 
						
							| 69 |  | simp2 |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> M e. ZZ ) | 
						
							| 70 | 68 43 69 | rspcdva |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( A /L 0 ) = ( ( A /L M ) x. ( A /L 0 ) ) ) | 
						
							| 71 | 70 | adantr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( A /L 0 ) = ( ( A /L M ) x. ( A /L 0 ) ) ) | 
						
							| 72 |  | oveq2 |  |-  ( N = 0 -> ( M x. N ) = ( M x. 0 ) ) | 
						
							| 73 | 69 | zcnd |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> M e. CC ) | 
						
							| 74 | 73 | mul01d |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( M x. 0 ) = 0 ) | 
						
							| 75 | 72 74 | sylan9eqr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( M x. N ) = 0 ) | 
						
							| 76 | 75 | oveq2d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( A /L ( M x. N ) ) = ( A /L 0 ) ) | 
						
							| 77 |  | simpr |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> N = 0 ) | 
						
							| 78 | 77 | oveq2d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( A /L N ) = ( A /L 0 ) ) | 
						
							| 79 | 78 | oveq2d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( ( A /L M ) x. ( A /L N ) ) = ( ( A /L M ) x. ( A /L 0 ) ) ) | 
						
							| 80 | 71 76 79 | 3eqtr4d |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ N = 0 ) -> ( A /L ( M x. N ) ) = ( ( A /L M ) x. ( A /L N ) ) ) | 
						
							| 81 |  | lgsdi |  |-  ( ( ( A e. ZZ /\ M e. ZZ /\ N e. ZZ ) /\ ( M =/= 0 /\ N =/= 0 ) ) -> ( A /L ( M x. N ) ) = ( ( A /L M ) x. ( A /L N ) ) ) | 
						
							| 82 | 21 81 | syl3anl1 |  |-  ( ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) /\ ( M =/= 0 /\ N =/= 0 ) ) -> ( A /L ( M x. N ) ) = ( ( A /L M ) x. ( A /L N ) ) ) | 
						
							| 83 | 65 80 82 | pm2.61da2ne |  |-  ( ( A e. NN0 /\ M e. ZZ /\ N e. ZZ ) -> ( A /L ( M x. N ) ) = ( ( A /L M ) x. ( A /L N ) ) ) |