| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mat1rhmval.k | ⊢ 𝐾  =  ( Base ‘ 𝑅 ) | 
						
							| 2 |  | mat1rhmval.a | ⊢ 𝐴  =  ( { 𝐸 }  Mat  𝑅 ) | 
						
							| 3 |  | mat1rhmval.b | ⊢ 𝐵  =  ( Base ‘ 𝐴 ) | 
						
							| 4 |  | mat1rhmval.o | ⊢ 𝑂  =  〈 𝐸 ,  𝐸 〉 | 
						
							| 5 |  | mat1rhmval.f | ⊢ 𝐹  =  ( 𝑥  ∈  𝐾  ↦  { 〈 𝑂 ,  𝑥 〉 } ) | 
						
							| 6 | 2 1 4 | mat1dimbas | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑋  ∈  𝐾 )  →  { 〈 𝑂 ,  𝑋 〉 }  ∈  ( Base ‘ 𝐴 ) ) | 
						
							| 7 | 1 2 3 4 5 | mat1rhmval | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑋  ∈  𝐾 )  →  ( 𝐹 ‘ 𝑋 )  =  { 〈 𝑂 ,  𝑋 〉 } ) | 
						
							| 8 | 3 | a1i | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑋  ∈  𝐾 )  →  𝐵  =  ( Base ‘ 𝐴 ) ) | 
						
							| 9 | 6 7 8 | 3eltr4d | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑋  ∈  𝐾 )  →  ( 𝐹 ‘ 𝑋 )  ∈  𝐵 ) |