| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mulgnndir.b |  |-  B = ( Base ` G ) | 
						
							| 2 |  | mulgnndir.t |  |-  .x. = ( .g ` G ) | 
						
							| 3 |  | mulgnndir.p |  |-  .+ = ( +g ` G ) | 
						
							| 4 |  | mndsgrp |  |-  ( G e. Mnd -> G e. Smgrp ) | 
						
							| 5 | 4 | adantr |  |-  ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) -> G e. Smgrp ) | 
						
							| 6 | 5 | ad2antrr |  |-  ( ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) /\ N e. NN ) -> G e. Smgrp ) | 
						
							| 7 |  | simplr |  |-  ( ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) /\ N e. NN ) -> M e. NN ) | 
						
							| 8 |  | simpr |  |-  ( ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) /\ N e. NN ) -> N e. NN ) | 
						
							| 9 |  | simpr3 |  |-  ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) -> X e. B ) | 
						
							| 10 | 9 | ad2antrr |  |-  ( ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) /\ N e. NN ) -> X e. B ) | 
						
							| 11 | 1 2 3 | mulgnndir |  |-  ( ( G e. Smgrp /\ ( M e. NN /\ N e. NN /\ X e. B ) ) -> ( ( M + N ) .x. X ) = ( ( M .x. X ) .+ ( N .x. X ) ) ) | 
						
							| 12 | 6 7 8 10 11 | syl13anc |  |-  ( ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) /\ N e. NN ) -> ( ( M + N ) .x. X ) = ( ( M .x. X ) .+ ( N .x. X ) ) ) | 
						
							| 13 |  | simpll |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> G e. Mnd ) | 
						
							| 14 |  | simpr1 |  |-  ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) -> M e. NN0 ) | 
						
							| 15 | 14 | adantr |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> M e. NN0 ) | 
						
							| 16 |  | simplr3 |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> X e. B ) | 
						
							| 17 | 1 2 13 15 16 | mulgnn0cld |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( M .x. X ) e. B ) | 
						
							| 18 |  | eqid |  |-  ( 0g ` G ) = ( 0g ` G ) | 
						
							| 19 | 1 3 18 | mndrid |  |-  ( ( G e. Mnd /\ ( M .x. X ) e. B ) -> ( ( M .x. X ) .+ ( 0g ` G ) ) = ( M .x. X ) ) | 
						
							| 20 | 13 17 19 | syl2anc |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( ( M .x. X ) .+ ( 0g ` G ) ) = ( M .x. X ) ) | 
						
							| 21 |  | simpr |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> N = 0 ) | 
						
							| 22 | 21 | oveq1d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( N .x. X ) = ( 0 .x. X ) ) | 
						
							| 23 | 1 18 2 | mulg0 |  |-  ( X e. B -> ( 0 .x. X ) = ( 0g ` G ) ) | 
						
							| 24 | 16 23 | syl |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( 0 .x. X ) = ( 0g ` G ) ) | 
						
							| 25 | 22 24 | eqtrd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( N .x. X ) = ( 0g ` G ) ) | 
						
							| 26 | 25 | oveq2d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( ( M .x. X ) .+ ( N .x. X ) ) = ( ( M .x. X ) .+ ( 0g ` G ) ) ) | 
						
							| 27 | 21 | oveq2d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( M + N ) = ( M + 0 ) ) | 
						
							| 28 | 15 | nn0cnd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> M e. CC ) | 
						
							| 29 | 28 | addridd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( M + 0 ) = M ) | 
						
							| 30 | 27 29 | eqtrd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( M + N ) = M ) | 
						
							| 31 | 30 | oveq1d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( ( M + N ) .x. X ) = ( M .x. X ) ) | 
						
							| 32 | 20 26 31 | 3eqtr4rd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ N = 0 ) -> ( ( M + N ) .x. X ) = ( ( M .x. X ) .+ ( N .x. X ) ) ) | 
						
							| 33 | 32 | adantlr |  |-  ( ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) /\ N = 0 ) -> ( ( M + N ) .x. X ) = ( ( M .x. X ) .+ ( N .x. X ) ) ) | 
						
							| 34 |  | simpr2 |  |-  ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) -> N e. NN0 ) | 
						
							| 35 |  | elnn0 |  |-  ( N e. NN0 <-> ( N e. NN \/ N = 0 ) ) | 
						
							| 36 | 34 35 | sylib |  |-  ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) -> ( N e. NN \/ N = 0 ) ) | 
						
							| 37 | 36 | adantr |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) -> ( N e. NN \/ N = 0 ) ) | 
						
							| 38 | 12 33 37 | mpjaodan |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M e. NN ) -> ( ( M + N ) .x. X ) = ( ( M .x. X ) .+ ( N .x. X ) ) ) | 
						
							| 39 |  | simpll |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> G e. Mnd ) | 
						
							| 40 |  | simplr2 |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> N e. NN0 ) | 
						
							| 41 |  | simplr3 |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> X e. B ) | 
						
							| 42 | 1 2 39 40 41 | mulgnn0cld |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( N .x. X ) e. B ) | 
						
							| 43 | 1 3 18 | mndlid |  |-  ( ( G e. Mnd /\ ( N .x. X ) e. B ) -> ( ( 0g ` G ) .+ ( N .x. X ) ) = ( N .x. X ) ) | 
						
							| 44 | 39 42 43 | syl2anc |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( ( 0g ` G ) .+ ( N .x. X ) ) = ( N .x. X ) ) | 
						
							| 45 |  | simpr |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> M = 0 ) | 
						
							| 46 | 45 | oveq1d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( M .x. X ) = ( 0 .x. X ) ) | 
						
							| 47 | 41 23 | syl |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( 0 .x. X ) = ( 0g ` G ) ) | 
						
							| 48 | 46 47 | eqtrd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( M .x. X ) = ( 0g ` G ) ) | 
						
							| 49 | 48 | oveq1d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( ( M .x. X ) .+ ( N .x. X ) ) = ( ( 0g ` G ) .+ ( N .x. X ) ) ) | 
						
							| 50 | 45 | oveq1d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( M + N ) = ( 0 + N ) ) | 
						
							| 51 | 40 | nn0cnd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> N e. CC ) | 
						
							| 52 | 51 | addlidd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( 0 + N ) = N ) | 
						
							| 53 | 50 52 | eqtrd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( M + N ) = N ) | 
						
							| 54 | 53 | oveq1d |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( ( M + N ) .x. X ) = ( N .x. X ) ) | 
						
							| 55 | 44 49 54 | 3eqtr4rd |  |-  ( ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) /\ M = 0 ) -> ( ( M + N ) .x. X ) = ( ( M .x. X ) .+ ( N .x. X ) ) ) | 
						
							| 56 |  | elnn0 |  |-  ( M e. NN0 <-> ( M e. NN \/ M = 0 ) ) | 
						
							| 57 | 14 56 | sylib |  |-  ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) -> ( M e. NN \/ M = 0 ) ) | 
						
							| 58 | 38 55 57 | mpjaodan |  |-  ( ( G e. Mnd /\ ( M e. NN0 /\ N e. NN0 /\ X e. B ) ) -> ( ( M + N ) .x. X ) = ( ( M .x. X ) .+ ( N .x. X ) ) ) |