| Step | Hyp | Ref | Expression | 
						
							| 1 |  | blocn.8 | ⊢ 𝐶  =  ( IndMet ‘ 𝑈 ) | 
						
							| 2 |  | blocn.d | ⊢ 𝐷  =  ( IndMet ‘ 𝑊 ) | 
						
							| 3 |  | blocn.j | ⊢ 𝐽  =  ( MetOpen ‘ 𝐶 ) | 
						
							| 4 |  | blocn.k | ⊢ 𝐾  =  ( MetOpen ‘ 𝐷 ) | 
						
							| 5 |  | blocn.5 | ⊢ 𝐵  =  ( 𝑈  BLnOp  𝑊 ) | 
						
							| 6 |  | blocn.u | ⊢ 𝑈  ∈  NrmCVec | 
						
							| 7 |  | blocn.w | ⊢ 𝑊  ∈  NrmCVec | 
						
							| 8 |  | blocn.4 | ⊢ 𝐿  =  ( 𝑈  LnOp  𝑊 ) | 
						
							| 9 |  | eleq1 | ⊢ ( 𝑇  =  if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  →  ( 𝑇  ∈  ( 𝐽  Cn  𝐾 )  ↔  if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  ∈  ( 𝐽  Cn  𝐾 ) ) ) | 
						
							| 10 |  | eleq1 | ⊢ ( 𝑇  =  if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  →  ( 𝑇  ∈  𝐵  ↔  if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  ∈  𝐵 ) ) | 
						
							| 11 | 9 10 | bibi12d | ⊢ ( 𝑇  =  if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  →  ( ( 𝑇  ∈  ( 𝐽  Cn  𝐾 )  ↔  𝑇  ∈  𝐵 )  ↔  ( if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  ∈  ( 𝐽  Cn  𝐾 )  ↔  if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  ∈  𝐵 ) ) ) | 
						
							| 12 |  | eqid | ⊢ ( 𝑈  0op  𝑊 )  =  ( 𝑈  0op  𝑊 ) | 
						
							| 13 | 12 8 | 0lno | ⊢ ( ( 𝑈  ∈  NrmCVec  ∧  𝑊  ∈  NrmCVec )  →  ( 𝑈  0op  𝑊 )  ∈  𝐿 ) | 
						
							| 14 | 6 7 13 | mp2an | ⊢ ( 𝑈  0op  𝑊 )  ∈  𝐿 | 
						
							| 15 | 14 | elimel | ⊢ if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  ∈  𝐿 | 
						
							| 16 | 1 2 3 4 8 5 6 7 15 | blocni | ⊢ ( if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  ∈  ( 𝐽  Cn  𝐾 )  ↔  if ( 𝑇  ∈  𝐿 ,  𝑇 ,  ( 𝑈  0op  𝑊 ) )  ∈  𝐵 ) | 
						
							| 17 | 11 16 | dedth | ⊢ ( 𝑇  ∈  𝐿  →  ( 𝑇  ∈  ( 𝐽  Cn  𝐾 )  ↔  𝑇  ∈  𝐵 ) ) |