| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mulgnn0z.b |  |-  B = ( Base ` G ) | 
						
							| 2 |  | mulgnn0z.t |  |-  .x. = ( .g ` G ) | 
						
							| 3 |  | mulgnn0z.o |  |-  .0. = ( 0g ` G ) | 
						
							| 4 |  | elnn0 |  |-  ( N e. NN0 <-> ( N e. NN \/ N = 0 ) ) | 
						
							| 5 |  | id |  |-  ( N e. NN -> N e. NN ) | 
						
							| 6 | 1 3 | mndidcl |  |-  ( G e. Mnd -> .0. e. B ) | 
						
							| 7 |  | eqid |  |-  ( +g ` G ) = ( +g ` G ) | 
						
							| 8 |  | eqid |  |-  seq 1 ( ( +g ` G ) , ( NN X. { .0. } ) ) = seq 1 ( ( +g ` G ) , ( NN X. { .0. } ) ) | 
						
							| 9 | 1 7 2 8 | mulgnn |  |-  ( ( N e. NN /\ .0. e. B ) -> ( N .x. .0. ) = ( seq 1 ( ( +g ` G ) , ( NN X. { .0. } ) ) ` N ) ) | 
						
							| 10 | 5 6 9 | syl2anr |  |-  ( ( G e. Mnd /\ N e. NN ) -> ( N .x. .0. ) = ( seq 1 ( ( +g ` G ) , ( NN X. { .0. } ) ) ` N ) ) | 
						
							| 11 | 1 7 3 | mndlid |  |-  ( ( G e. Mnd /\ .0. e. B ) -> ( .0. ( +g ` G ) .0. ) = .0. ) | 
						
							| 12 | 6 11 | mpdan |  |-  ( G e. Mnd -> ( .0. ( +g ` G ) .0. ) = .0. ) | 
						
							| 13 | 12 | adantr |  |-  ( ( G e. Mnd /\ N e. NN ) -> ( .0. ( +g ` G ) .0. ) = .0. ) | 
						
							| 14 |  | simpr |  |-  ( ( G e. Mnd /\ N e. NN ) -> N e. NN ) | 
						
							| 15 |  | nnuz |  |-  NN = ( ZZ>= ` 1 ) | 
						
							| 16 | 14 15 | eleqtrdi |  |-  ( ( G e. Mnd /\ N e. NN ) -> N e. ( ZZ>= ` 1 ) ) | 
						
							| 17 | 6 | adantr |  |-  ( ( G e. Mnd /\ N e. NN ) -> .0. e. B ) | 
						
							| 18 |  | elfznn |  |-  ( x e. ( 1 ... N ) -> x e. NN ) | 
						
							| 19 |  | fvconst2g |  |-  ( ( .0. e. B /\ x e. NN ) -> ( ( NN X. { .0. } ) ` x ) = .0. ) | 
						
							| 20 | 17 18 19 | syl2an |  |-  ( ( ( G e. Mnd /\ N e. NN ) /\ x e. ( 1 ... N ) ) -> ( ( NN X. { .0. } ) ` x ) = .0. ) | 
						
							| 21 | 13 16 20 | seqid3 |  |-  ( ( G e. Mnd /\ N e. NN ) -> ( seq 1 ( ( +g ` G ) , ( NN X. { .0. } ) ) ` N ) = .0. ) | 
						
							| 22 | 10 21 | eqtrd |  |-  ( ( G e. Mnd /\ N e. NN ) -> ( N .x. .0. ) = .0. ) | 
						
							| 23 |  | oveq1 |  |-  ( N = 0 -> ( N .x. .0. ) = ( 0 .x. .0. ) ) | 
						
							| 24 | 1 3 2 | mulg0 |  |-  ( .0. e. B -> ( 0 .x. .0. ) = .0. ) | 
						
							| 25 | 6 24 | syl |  |-  ( G e. Mnd -> ( 0 .x. .0. ) = .0. ) | 
						
							| 26 | 23 25 | sylan9eqr |  |-  ( ( G e. Mnd /\ N = 0 ) -> ( N .x. .0. ) = .0. ) | 
						
							| 27 | 22 26 | jaodan |  |-  ( ( G e. Mnd /\ ( N e. NN \/ N = 0 ) ) -> ( N .x. .0. ) = .0. ) | 
						
							| 28 | 4 27 | sylan2b |  |-  ( ( G e. Mnd /\ N e. NN0 ) -> ( N .x. .0. ) = .0. ) |