| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdetuni.a | ⊢ 𝐴  =  ( 𝑁  Mat  𝑅 ) | 
						
							| 2 |  | mdetuni.b | ⊢ 𝐵  =  ( Base ‘ 𝐴 ) | 
						
							| 3 |  | mdetuni.k | ⊢ 𝐾  =  ( Base ‘ 𝑅 ) | 
						
							| 4 |  | mdetuni.0g | ⊢  0   =  ( 0g ‘ 𝑅 ) | 
						
							| 5 |  | mdetuni.1r | ⊢  1   =  ( 1r ‘ 𝑅 ) | 
						
							| 6 |  | mdetuni.pg | ⊢  +   =  ( +g ‘ 𝑅 ) | 
						
							| 7 |  | mdetuni.tg | ⊢  ·   =  ( .r ‘ 𝑅 ) | 
						
							| 8 |  | mdetuni.n | ⊢ ( 𝜑  →  𝑁  ∈  Fin ) | 
						
							| 9 |  | mdetuni.r | ⊢ ( 𝜑  →  𝑅  ∈  Ring ) | 
						
							| 10 |  | mdetuni.ff | ⊢ ( 𝜑  →  𝐷 : 𝐵 ⟶ 𝐾 ) | 
						
							| 11 |  | mdetuni.al | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝑁 ∀ 𝑧  ∈  𝑁 ( ( 𝑦  ≠  𝑧  ∧  ∀ 𝑤  ∈  𝑁 ( 𝑦 𝑥 𝑤 )  =  ( 𝑧 𝑥 𝑤 ) )  →  ( 𝐷 ‘ 𝑥 )  =   0  ) ) | 
						
							| 12 |  | mdetuni.li | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ∀ 𝑤  ∈  𝑁 ( ( ( 𝑥  ↾  ( { 𝑤 }  ×  𝑁 ) )  =  ( ( 𝑦  ↾  ( { 𝑤 }  ×  𝑁 ) )  ∘f   +  ( 𝑧  ↾  ( { 𝑤 }  ×  𝑁 ) ) )  ∧  ( 𝑥  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  =  ( 𝑦  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  ∧  ( 𝑥  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  =  ( 𝑧  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) ) )  →  ( 𝐷 ‘ 𝑥 )  =  ( ( 𝐷 ‘ 𝑦 )  +  ( 𝐷 ‘ 𝑧 ) ) ) ) | 
						
							| 13 |  | mdetuni.sc | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐾 ∀ 𝑧  ∈  𝐵 ∀ 𝑤  ∈  𝑁 ( ( ( 𝑥  ↾  ( { 𝑤 }  ×  𝑁 ) )  =  ( ( ( { 𝑤 }  ×  𝑁 )  ×  { 𝑦 } )  ∘f   ·  ( 𝑧  ↾  ( { 𝑤 }  ×  𝑁 ) ) )  ∧  ( 𝑥  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  =  ( 𝑧  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) ) )  →  ( 𝐷 ‘ 𝑥 )  =  ( 𝑦  ·  ( 𝐷 ‘ 𝑧 ) ) ) ) | 
						
							| 14 |  | mdetunilem6.ph | ⊢ ( 𝜓  →  𝜑 ) | 
						
							| 15 |  | mdetunilem6.ef | ⊢ ( 𝜓  →  ( 𝐸  ∈  𝑁  ∧  𝐹  ∈  𝑁  ∧  𝐸  ≠  𝐹 ) ) | 
						
							| 16 |  | mdetunilem6.gh | ⊢ ( ( 𝜓  ∧  𝑏  ∈  𝑁 )  →  ( 𝐺  ∈  𝐾  ∧  𝐻  ∈  𝐾 ) ) | 
						
							| 17 |  | mdetunilem6.i | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝐼  ∈  𝐾 ) | 
						
							| 18 | 15 | simp1d | ⊢ ( 𝜓  →  𝐸  ∈  𝑁 ) | 
						
							| 19 | 16 | simprd | ⊢ ( ( 𝜓  ∧  𝑏  ∈  𝑁 )  →  𝐻  ∈  𝐾 ) | 
						
							| 20 | 19 | 3adant2 | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝐻  ∈  𝐾 ) | 
						
							| 21 | 16 | simpld | ⊢ ( ( 𝜓  ∧  𝑏  ∈  𝑁 )  →  𝐺  ∈  𝐾 ) | 
						
							| 22 | 21 | 3adant2 | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝐺  ∈  𝐾 ) | 
						
							| 23 |  | ringgrp | ⊢ ( 𝑅  ∈  Ring  →  𝑅  ∈  Grp ) | 
						
							| 24 | 14 9 23 | 3syl | ⊢ ( 𝜓  →  𝑅  ∈  Grp ) | 
						
							| 25 | 24 | adantr | ⊢ ( ( 𝜓  ∧  𝑏  ∈  𝑁 )  →  𝑅  ∈  Grp ) | 
						
							| 26 | 3 6 | grpcl | ⊢ ( ( 𝑅  ∈  Grp  ∧  𝐻  ∈  𝐾  ∧  𝐺  ∈  𝐾 )  →  ( 𝐻  +  𝐺 )  ∈  𝐾 ) | 
						
							| 27 | 25 19 21 26 | syl3anc | ⊢ ( ( 𝜓  ∧  𝑏  ∈  𝑁 )  →  ( 𝐻  +  𝐺 )  ∈  𝐾 ) | 
						
							| 28 | 27 | 3adant2 | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  ( 𝐻  +  𝐺 )  ∈  𝐾 ) | 
						
							| 29 | 28 17 | ifcld | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 )  ∈  𝐾 ) | 
						
							| 30 | 20 22 29 | 3jca | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  ( 𝐻  ∈  𝐾  ∧  𝐺  ∈  𝐾  ∧  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 )  ∈  𝐾 ) ) | 
						
							| 31 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 18 30 | mdetunilem5 | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  =  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) ) ) ) | 
						
							| 32 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 27 17 | mdetunilem2 | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  =   0  ) | 
						
							| 33 | 15 | simp2d | ⊢ ( 𝜓  →  𝐹  ∈  𝑁 ) | 
						
							| 34 | 20 17 | ifcld | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 )  ∈  𝐾 ) | 
						
							| 35 | 20 22 34 | 3jca | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  ( 𝐻  ∈  𝐾  ∧  𝐺  ∈  𝐾  ∧  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 )  ∈  𝐾 ) ) | 
						
							| 36 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 33 35 | mdetunilem5 | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) )  =  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) ) ) | 
						
							| 37 | 15 | simp3d | ⊢ ( 𝜓  →  𝐸  ≠  𝐹 ) | 
						
							| 38 | 37 | necomd | ⊢ ( 𝜓  →  𝐹  ≠  𝐸 ) | 
						
							| 39 | 33 18 38 | 3jca | ⊢ ( 𝜓  →  ( 𝐹  ∈  𝑁  ∧  𝐸  ∈  𝑁  ∧  𝐹  ≠  𝐸 ) ) | 
						
							| 40 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 39 19 17 | mdetunilem2 | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) )  =   0  ) | 
						
							| 41 | 40 | oveq1d | ⊢ ( 𝜓  →  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) )  =  (  0   +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) ) ) | 
						
							| 42 | 37 | neneqd | ⊢ ( 𝜓  →  ¬  𝐸  =  𝐹 ) | 
						
							| 43 |  | eqtr2 | ⊢ ( ( 𝑎  =  𝐸  ∧  𝑎  =  𝐹 )  →  𝐸  =  𝐹 ) | 
						
							| 44 | 42 43 | nsyl | ⊢ ( 𝜓  →  ¬  ( 𝑎  =  𝐸  ∧  𝑎  =  𝐹 ) ) | 
						
							| 45 | 44 | 3ad2ant1 | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  ¬  ( 𝑎  =  𝐸  ∧  𝑎  =  𝐹 ) ) | 
						
							| 46 |  | ifcomnan | ⊢ ( ¬  ( 𝑎  =  𝐸  ∧  𝑎  =  𝐹 )  →  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) | 
						
							| 47 | 45 46 | syl | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) | 
						
							| 48 | 47 | mpoeq3dva | ⊢ ( 𝜓  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) )  =  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) | 
						
							| 49 | 48 | fveq2d | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) ) | 
						
							| 50 | 14 10 | syl | ⊢ ( 𝜓  →  𝐷 : 𝐵 ⟶ 𝐾 ) | 
						
							| 51 | 14 8 | syl | ⊢ ( 𝜓  →  𝑁  ∈  Fin ) | 
						
							| 52 | 22 17 | ifcld | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 )  ∈  𝐾 ) | 
						
							| 53 | 20 52 | ifcld | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) )  ∈  𝐾 ) | 
						
							| 54 | 1 3 2 51 24 53 | matbas2d | ⊢ ( 𝜓  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) )  ∈  𝐵 ) | 
						
							| 55 | 50 54 | ffvelcdmd | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) )  ∈  𝐾 ) | 
						
							| 56 | 49 55 | eqeltrrd | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) )  ∈  𝐾 ) | 
						
							| 57 | 3 6 4 | grplid | ⊢ ( ( 𝑅  ∈  Grp  ∧  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) )  ∈  𝐾 )  →  (  0   +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) ) | 
						
							| 58 | 24 56 57 | syl2anc | ⊢ ( 𝜓  →  (  0   +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) ) | 
						
							| 59 | 36 41 58 | 3eqtrd | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) ) | 
						
							| 60 |  | ifcomnan | ⊢ ( ¬  ( 𝑎  =  𝐸  ∧  𝑎  =  𝐹 )  →  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) | 
						
							| 61 | 45 60 | syl | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) | 
						
							| 62 | 61 | mpoeq3dva | ⊢ ( 𝜓  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) )  =  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) | 
						
							| 63 | 62 | fveq2d | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐻 ,  𝐼 ) ) ) ) ) | 
						
							| 64 | 59 63 49 | 3eqtr4d | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) ) ) | 
						
							| 65 | 22 17 | ifcld | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 )  ∈  𝐾 ) | 
						
							| 66 | 20 22 65 | 3jca | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  ( 𝐻  ∈  𝐾  ∧  𝐺  ∈  𝐾  ∧  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 )  ∈  𝐾 ) ) | 
						
							| 67 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 33 66 | mdetunilem5 | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  =  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) ) ) | 
						
							| 68 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 39 21 17 | mdetunilem2 | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  =   0  ) | 
						
							| 69 | 68 | oveq2d | ⊢ ( 𝜓  →  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐺 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) )  =  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  +   0  ) ) | 
						
							| 70 |  | ifcomnan | ⊢ ( ¬  ( 𝑎  =  𝐸  ∧  𝑎  =  𝐹 )  →  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) | 
						
							| 71 | 45 70 | syl | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) | 
						
							| 72 | 71 | mpoeq3dva | ⊢ ( 𝜓  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) )  =  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) | 
						
							| 73 | 72 | fveq2d | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) ) | 
						
							| 74 | 20 17 | ifcld | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 )  ∈  𝐾 ) | 
						
							| 75 | 22 74 | ifcld | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) )  ∈  𝐾 ) | 
						
							| 76 | 1 3 2 51 24 75 | matbas2d | ⊢ ( 𝜓  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) )  ∈  𝐵 ) | 
						
							| 77 | 50 76 | ffvelcdmd | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) )  ∈  𝐾 ) | 
						
							| 78 | 73 77 | eqeltrrd | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  ∈  𝐾 ) | 
						
							| 79 | 3 6 4 | grprid | ⊢ ( ( 𝑅  ∈  Grp  ∧  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  ∈  𝐾 )  →  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  +   0  )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) ) | 
						
							| 80 | 24 78 79 | syl2anc | ⊢ ( 𝜓  →  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  +   0  )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) ) | 
						
							| 81 | 67 69 80 | 3eqtrd | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  𝐻 ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) ) | 
						
							| 82 |  | ifcomnan | ⊢ ( ¬  ( 𝑎  =  𝐸  ∧  𝑎  =  𝐹 )  →  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) | 
						
							| 83 | 45 82 | syl | ⊢ ( ( 𝜓  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) )  =  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) | 
						
							| 84 | 83 | mpoeq3dva | ⊢ ( 𝜓  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) )  =  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) | 
						
							| 85 | 84 | fveq2d | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  if ( 𝑎  =  𝐸 ,  𝐺 ,  𝐼 ) ) ) ) ) | 
						
							| 86 | 81 85 73 | 3eqtr4d | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) ) ) | 
						
							| 87 | 64 86 | oveq12d | ⊢ ( 𝜓  →  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  ( 𝐻  +  𝐺 ) ,  𝐼 ) ) ) ) )  =  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) ) ) ) | 
						
							| 88 | 31 32 87 | 3eqtr3rd | ⊢ ( 𝜓  →  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) ) )  =   0  ) | 
						
							| 89 |  | eqid | ⊢ ( invg ‘ 𝑅 )  =  ( invg ‘ 𝑅 ) | 
						
							| 90 | 3 6 4 89 | grpinvid1 | ⊢ ( ( 𝑅  ∈  Grp  ∧  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) )  ∈  𝐾  ∧  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) )  ∈  𝐾 )  →  ( ( ( invg ‘ 𝑅 ) ‘ ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) )  ↔  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) ) )  =   0  ) ) | 
						
							| 91 | 24 55 77 90 | syl3anc | ⊢ ( 𝜓  →  ( ( ( invg ‘ 𝑅 ) ‘ ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) )  ↔  ( ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) )  +  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) ) )  =   0  ) ) | 
						
							| 92 | 88 91 | mpbird | ⊢ ( 𝜓  →  ( ( invg ‘ 𝑅 ) ‘ ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) ) ) | 
						
							| 93 | 92 | eqcomd | ⊢ ( 𝜓  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐺 ,  if ( 𝑎  =  𝐹 ,  𝐻 ,  𝐼 ) ) ) )  =  ( ( invg ‘ 𝑅 ) ‘ ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝐸 ,  𝐻 ,  if ( 𝑎  =  𝐹 ,  𝐺 ,  𝐼 ) ) ) ) ) ) |