| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cpm2mfval.i | ⊢ 𝐼  =  ( 𝑁  cPolyMatToMat  𝑅 ) | 
						
							| 2 |  | cpm2mfval.s | ⊢ 𝑆  =  ( 𝑁  ConstPolyMat  𝑅 ) | 
						
							| 3 | 1 2 | cpm2mfval | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉 )  →  𝐼  =  ( 𝑚  ∈  𝑆  ↦  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑚 𝑦 ) ) ‘ 0 ) ) ) ) | 
						
							| 4 | 3 | 3adant3 | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉  ∧  𝑀  ∈  𝑆 )  →  𝐼  =  ( 𝑚  ∈  𝑆  ↦  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑚 𝑦 ) ) ‘ 0 ) ) ) ) | 
						
							| 5 |  | oveq | ⊢ ( 𝑚  =  𝑀  →  ( 𝑥 𝑚 𝑦 )  =  ( 𝑥 𝑀 𝑦 ) ) | 
						
							| 6 | 5 | fveq2d | ⊢ ( 𝑚  =  𝑀  →  ( coe1 ‘ ( 𝑥 𝑚 𝑦 ) )  =  ( coe1 ‘ ( 𝑥 𝑀 𝑦 ) ) ) | 
						
							| 7 | 6 | fveq1d | ⊢ ( 𝑚  =  𝑀  →  ( ( coe1 ‘ ( 𝑥 𝑚 𝑦 ) ) ‘ 0 )  =  ( ( coe1 ‘ ( 𝑥 𝑀 𝑦 ) ) ‘ 0 ) ) | 
						
							| 8 | 7 | mpoeq3dv | ⊢ ( 𝑚  =  𝑀  →  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑚 𝑦 ) ) ‘ 0 ) )  =  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑀 𝑦 ) ) ‘ 0 ) ) ) | 
						
							| 9 | 8 | adantl | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉  ∧  𝑀  ∈  𝑆 )  ∧  𝑚  =  𝑀 )  →  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑚 𝑦 ) ) ‘ 0 ) )  =  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑀 𝑦 ) ) ‘ 0 ) ) ) | 
						
							| 10 |  | simp3 | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉  ∧  𝑀  ∈  𝑆 )  →  𝑀  ∈  𝑆 ) | 
						
							| 11 |  | simp1 | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉  ∧  𝑀  ∈  𝑆 )  →  𝑁  ∈  Fin ) | 
						
							| 12 |  | mpoexga | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑁  ∈  Fin )  →  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑀 𝑦 ) ) ‘ 0 ) )  ∈  V ) | 
						
							| 13 | 11 11 12 | syl2anc | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉  ∧  𝑀  ∈  𝑆 )  →  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑀 𝑦 ) ) ‘ 0 ) )  ∈  V ) | 
						
							| 14 | 4 9 10 13 | fvmptd | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉  ∧  𝑀  ∈  𝑆 )  →  ( 𝐼 ‘ 𝑀 )  =  ( 𝑥  ∈  𝑁 ,  𝑦  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑥 𝑀 𝑦 ) ) ‘ 0 ) ) ) |