| Step | Hyp | Ref | Expression | 
						
							| 1 |  | setsms.x | ⊢ ( 𝜑  →  𝑋  =  ( Base ‘ 𝑀 ) ) | 
						
							| 2 |  | setsms.d | ⊢ ( 𝜑  →  𝐷  =  ( ( dist ‘ 𝑀 )  ↾  ( 𝑋  ×  𝑋 ) ) ) | 
						
							| 3 |  | setsms.k | ⊢ ( 𝜑  →  𝐾  =  ( 𝑀  sSet  〈 ( TopSet ‘ ndx ) ,  ( MetOpen ‘ 𝐷 ) 〉 ) ) | 
						
							| 4 |  | baseid | ⊢ Base  =  Slot  ( Base ‘ ndx ) | 
						
							| 5 |  | 1re | ⊢ 1  ∈  ℝ | 
						
							| 6 |  | 1lt9 | ⊢ 1  <  9 | 
						
							| 7 | 5 6 | ltneii | ⊢ 1  ≠  9 | 
						
							| 8 |  | basendx | ⊢ ( Base ‘ ndx )  =  1 | 
						
							| 9 |  | tsetndx | ⊢ ( TopSet ‘ ndx )  =  9 | 
						
							| 10 | 8 9 | neeq12i | ⊢ ( ( Base ‘ ndx )  ≠  ( TopSet ‘ ndx )  ↔  1  ≠  9 ) | 
						
							| 11 | 7 10 | mpbir | ⊢ ( Base ‘ ndx )  ≠  ( TopSet ‘ ndx ) | 
						
							| 12 | 4 11 | setsnid | ⊢ ( Base ‘ 𝑀 )  =  ( Base ‘ ( 𝑀  sSet  〈 ( TopSet ‘ ndx ) ,  ( MetOpen ‘ 𝐷 ) 〉 ) ) | 
						
							| 13 | 3 | fveq2d | ⊢ ( 𝜑  →  ( Base ‘ 𝐾 )  =  ( Base ‘ ( 𝑀  sSet  〈 ( TopSet ‘ ndx ) ,  ( MetOpen ‘ 𝐷 ) 〉 ) ) ) | 
						
							| 14 | 12 1 13 | 3eqtr4a | ⊢ ( 𝜑  →  𝑋  =  ( Base ‘ 𝐾 ) ) |