| Step | Hyp | Ref | Expression | 
						
							| 1 |  | istmd.1 | ⊢ 𝐹  =  ( +𝑓 ‘ 𝐺 ) | 
						
							| 2 |  | istmd.2 | ⊢ 𝐽  =  ( TopOpen ‘ 𝐺 ) | 
						
							| 3 |  | elin | ⊢ ( 𝐺  ∈  ( Mnd  ∩  TopSp )  ↔  ( 𝐺  ∈  Mnd  ∧  𝐺  ∈  TopSp ) ) | 
						
							| 4 | 3 | anbi1i | ⊢ ( ( 𝐺  ∈  ( Mnd  ∩  TopSp )  ∧  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) )  ↔  ( ( 𝐺  ∈  Mnd  ∧  𝐺  ∈  TopSp )  ∧  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) ) | 
						
							| 5 |  | fvexd | ⊢ ( 𝑓  =  𝐺  →  ( TopOpen ‘ 𝑓 )  ∈  V ) | 
						
							| 6 |  | simpl | ⊢ ( ( 𝑓  =  𝐺  ∧  𝑗  =  ( TopOpen ‘ 𝑓 ) )  →  𝑓  =  𝐺 ) | 
						
							| 7 | 6 | fveq2d | ⊢ ( ( 𝑓  =  𝐺  ∧  𝑗  =  ( TopOpen ‘ 𝑓 ) )  →  ( +𝑓 ‘ 𝑓 )  =  ( +𝑓 ‘ 𝐺 ) ) | 
						
							| 8 | 7 1 | eqtr4di | ⊢ ( ( 𝑓  =  𝐺  ∧  𝑗  =  ( TopOpen ‘ 𝑓 ) )  →  ( +𝑓 ‘ 𝑓 )  =  𝐹 ) | 
						
							| 9 |  | id | ⊢ ( 𝑗  =  ( TopOpen ‘ 𝑓 )  →  𝑗  =  ( TopOpen ‘ 𝑓 ) ) | 
						
							| 10 |  | fveq2 | ⊢ ( 𝑓  =  𝐺  →  ( TopOpen ‘ 𝑓 )  =  ( TopOpen ‘ 𝐺 ) ) | 
						
							| 11 | 10 2 | eqtr4di | ⊢ ( 𝑓  =  𝐺  →  ( TopOpen ‘ 𝑓 )  =  𝐽 ) | 
						
							| 12 | 9 11 | sylan9eqr | ⊢ ( ( 𝑓  =  𝐺  ∧  𝑗  =  ( TopOpen ‘ 𝑓 ) )  →  𝑗  =  𝐽 ) | 
						
							| 13 | 12 12 | oveq12d | ⊢ ( ( 𝑓  =  𝐺  ∧  𝑗  =  ( TopOpen ‘ 𝑓 ) )  →  ( 𝑗  ×t  𝑗 )  =  ( 𝐽  ×t  𝐽 ) ) | 
						
							| 14 | 13 12 | oveq12d | ⊢ ( ( 𝑓  =  𝐺  ∧  𝑗  =  ( TopOpen ‘ 𝑓 ) )  →  ( ( 𝑗  ×t  𝑗 )  Cn  𝑗 )  =  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) | 
						
							| 15 | 8 14 | eleq12d | ⊢ ( ( 𝑓  =  𝐺  ∧  𝑗  =  ( TopOpen ‘ 𝑓 ) )  →  ( ( +𝑓 ‘ 𝑓 )  ∈  ( ( 𝑗  ×t  𝑗 )  Cn  𝑗 )  ↔  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) ) | 
						
							| 16 | 5 15 | sbcied | ⊢ ( 𝑓  =  𝐺  →  ( [ ( TopOpen ‘ 𝑓 )  /  𝑗 ] ( +𝑓 ‘ 𝑓 )  ∈  ( ( 𝑗  ×t  𝑗 )  Cn  𝑗 )  ↔  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) ) | 
						
							| 17 |  | df-tmd | ⊢ TopMnd  =  { 𝑓  ∈  ( Mnd  ∩  TopSp )  ∣  [ ( TopOpen ‘ 𝑓 )  /  𝑗 ] ( +𝑓 ‘ 𝑓 )  ∈  ( ( 𝑗  ×t  𝑗 )  Cn  𝑗 ) } | 
						
							| 18 | 16 17 | elrab2 | ⊢ ( 𝐺  ∈  TopMnd  ↔  ( 𝐺  ∈  ( Mnd  ∩  TopSp )  ∧  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) ) | 
						
							| 19 |  | df-3an | ⊢ ( ( 𝐺  ∈  Mnd  ∧  𝐺  ∈  TopSp  ∧  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) )  ↔  ( ( 𝐺  ∈  Mnd  ∧  𝐺  ∈  TopSp )  ∧  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) ) | 
						
							| 20 | 4 18 19 | 3bitr4i | ⊢ ( 𝐺  ∈  TopMnd  ↔  ( 𝐺  ∈  Mnd  ∧  𝐺  ∈  TopSp  ∧  𝐹  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) ) |