| Step | Hyp | Ref | Expression | 
						
							| 1 |  | marepvfval.a | ⊢ 𝐴  =  ( 𝑁  Mat  𝑅 ) | 
						
							| 2 |  | marepvfval.b | ⊢ 𝐵  =  ( Base ‘ 𝐴 ) | 
						
							| 3 |  | marepvfval.q | ⊢ 𝑄  =  ( 𝑁  matRepV  𝑅 ) | 
						
							| 4 |  | marepvfval.v | ⊢ 𝑉  =  ( ( Base ‘ 𝑅 )  ↑m  𝑁 ) | 
						
							| 5 | 1 2 3 4 | marepvval | ⊢ ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  →  ( ( 𝑀 𝑄 𝐶 ) ‘ 𝐾 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  if ( 𝑗  =  𝐾 ,  ( 𝐶 ‘ 𝑖 ) ,  ( 𝑖 𝑀 𝑗 ) ) ) ) | 
						
							| 6 | 5 | adantr | ⊢ ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  →  ( ( 𝑀 𝑄 𝐶 ) ‘ 𝐾 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  if ( 𝑗  =  𝐾 ,  ( 𝐶 ‘ 𝑖 ) ,  ( 𝑖 𝑀 𝑗 ) ) ) ) | 
						
							| 7 |  | simprl | ⊢ ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  →  𝐼  ∈  𝑁 ) | 
						
							| 8 |  | simplrr | ⊢ ( ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  ∧  𝑖  =  𝐼 )  →  𝐽  ∈  𝑁 ) | 
						
							| 9 |  | fvexd | ⊢ ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  →  ( 𝐶 ‘ 𝑖 )  ∈  V ) | 
						
							| 10 |  | ovexd | ⊢ ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  →  ( 𝑖 𝑀 𝑗 )  ∈  V ) | 
						
							| 11 | 9 10 | ifcld | ⊢ ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  →  if ( 𝑗  =  𝐾 ,  ( 𝐶 ‘ 𝑖 ) ,  ( 𝑖 𝑀 𝑗 ) )  ∈  V ) | 
						
							| 12 | 11 | adantr | ⊢ ( ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  ∧  ( 𝑖  =  𝐼  ∧  𝑗  =  𝐽 ) )  →  if ( 𝑗  =  𝐾 ,  ( 𝐶 ‘ 𝑖 ) ,  ( 𝑖 𝑀 𝑗 ) )  ∈  V ) | 
						
							| 13 |  | eqeq1 | ⊢ ( 𝑗  =  𝐽  →  ( 𝑗  =  𝐾  ↔  𝐽  =  𝐾 ) ) | 
						
							| 14 | 13 | adantl | ⊢ ( ( 𝑖  =  𝐼  ∧  𝑗  =  𝐽 )  →  ( 𝑗  =  𝐾  ↔  𝐽  =  𝐾 ) ) | 
						
							| 15 |  | fveq2 | ⊢ ( 𝑖  =  𝐼  →  ( 𝐶 ‘ 𝑖 )  =  ( 𝐶 ‘ 𝐼 ) ) | 
						
							| 16 | 15 | adantr | ⊢ ( ( 𝑖  =  𝐼  ∧  𝑗  =  𝐽 )  →  ( 𝐶 ‘ 𝑖 )  =  ( 𝐶 ‘ 𝐼 ) ) | 
						
							| 17 |  | oveq12 | ⊢ ( ( 𝑖  =  𝐼  ∧  𝑗  =  𝐽 )  →  ( 𝑖 𝑀 𝑗 )  =  ( 𝐼 𝑀 𝐽 ) ) | 
						
							| 18 | 14 16 17 | ifbieq12d | ⊢ ( ( 𝑖  =  𝐼  ∧  𝑗  =  𝐽 )  →  if ( 𝑗  =  𝐾 ,  ( 𝐶 ‘ 𝑖 ) ,  ( 𝑖 𝑀 𝑗 ) )  =  if ( 𝐽  =  𝐾 ,  ( 𝐶 ‘ 𝐼 ) ,  ( 𝐼 𝑀 𝐽 ) ) ) | 
						
							| 19 | 18 | adantl | ⊢ ( ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  ∧  ( 𝑖  =  𝐼  ∧  𝑗  =  𝐽 ) )  →  if ( 𝑗  =  𝐾 ,  ( 𝐶 ‘ 𝑖 ) ,  ( 𝑖 𝑀 𝑗 ) )  =  if ( 𝐽  =  𝐾 ,  ( 𝐶 ‘ 𝐼 ) ,  ( 𝐼 𝑀 𝐽 ) ) ) | 
						
							| 20 | 7 8 12 19 | ovmpodv2 | ⊢ ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  →  ( ( ( 𝑀 𝑄 𝐶 ) ‘ 𝐾 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  if ( 𝑗  =  𝐾 ,  ( 𝐶 ‘ 𝑖 ) ,  ( 𝑖 𝑀 𝑗 ) ) )  →  ( 𝐼 ( ( 𝑀 𝑄 𝐶 ) ‘ 𝐾 ) 𝐽 )  =  if ( 𝐽  =  𝐾 ,  ( 𝐶 ‘ 𝐼 ) ,  ( 𝐼 𝑀 𝐽 ) ) ) ) | 
						
							| 21 | 6 20 | mpd | ⊢ ( ( ( 𝑀  ∈  𝐵  ∧  𝐶  ∈  𝑉  ∧  𝐾  ∈  𝑁 )  ∧  ( 𝐼  ∈  𝑁  ∧  𝐽  ∈  𝑁 ) )  →  ( 𝐼 ( ( 𝑀 𝑄 𝐶 ) ‘ 𝐾 ) 𝐽 )  =  if ( 𝐽  =  𝐾 ,  ( 𝐶 ‘ 𝐼 ) ,  ( 𝐼 𝑀 𝐽 ) ) ) |