| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mulrcn.j | ⊢ 𝐽  =  ( TopOpen ‘ 𝑅 ) | 
						
							| 2 |  | cnmpt1mulr.t | ⊢  ·   =  ( .r ‘ 𝑅 ) | 
						
							| 3 |  | cnmpt1mulr.r | ⊢ ( 𝜑  →  𝑅  ∈  TopRing ) | 
						
							| 4 |  | cnmpt1mulr.k | ⊢ ( 𝜑  →  𝐾  ∈  ( TopOn ‘ 𝑋 ) ) | 
						
							| 5 |  | cnmpt2mulr.l | ⊢ ( 𝜑  →  𝐿  ∈  ( TopOn ‘ 𝑌 ) ) | 
						
							| 6 |  | cnmpt2mulr.a | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝑋 ,  𝑦  ∈  𝑌  ↦  𝐴 )  ∈  ( ( 𝐾  ×t  𝐿 )  Cn  𝐽 ) ) | 
						
							| 7 |  | cnmpt2mulr.b | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝑋 ,  𝑦  ∈  𝑌  ↦  𝐵 )  ∈  ( ( 𝐾  ×t  𝐿 )  Cn  𝐽 ) ) | 
						
							| 8 |  | eqid | ⊢ ( mulGrp ‘ 𝑅 )  =  ( mulGrp ‘ 𝑅 ) | 
						
							| 9 | 8 1 | mgptopn | ⊢ 𝐽  =  ( TopOpen ‘ ( mulGrp ‘ 𝑅 ) ) | 
						
							| 10 | 8 2 | mgpplusg | ⊢  ·   =  ( +g ‘ ( mulGrp ‘ 𝑅 ) ) | 
						
							| 11 | 8 | trgtmd | ⊢ ( 𝑅  ∈  TopRing  →  ( mulGrp ‘ 𝑅 )  ∈  TopMnd ) | 
						
							| 12 | 3 11 | syl | ⊢ ( 𝜑  →  ( mulGrp ‘ 𝑅 )  ∈  TopMnd ) | 
						
							| 13 | 9 10 12 4 5 6 7 | cnmpt2plusg | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝑋 ,  𝑦  ∈  𝑌  ↦  ( 𝐴  ·  𝐵 ) )  ∈  ( ( 𝐾  ×t  𝐿 )  Cn  𝐽 ) ) |