| Step | Hyp | Ref | Expression | 
						
							| 1 |  | prdsbasmpt2.y | ⊢ 𝑌  =  ( 𝑆 Xs ( 𝑥  ∈  𝐼  ↦  𝑅 ) ) | 
						
							| 2 |  | prdsbasmpt2.b | ⊢ 𝐵  =  ( Base ‘ 𝑌 ) | 
						
							| 3 |  | prdsbasmpt2.s | ⊢ ( 𝜑  →  𝑆  ∈  𝑉 ) | 
						
							| 4 |  | prdsbasmpt2.i | ⊢ ( 𝜑  →  𝐼  ∈  𝑊 ) | 
						
							| 5 |  | prdsbasmpt2.r | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐼 𝑅  ∈  𝑋 ) | 
						
							| 6 |  | prdsbasmpt2.k | ⊢ 𝐾  =  ( Base ‘ 𝑅 ) | 
						
							| 7 | 1 2 3 4 5 6 | prdsbas3 | ⊢ ( 𝜑  →  𝐵  =  X 𝑥  ∈  𝐼 𝐾 ) | 
						
							| 8 | 7 | eleq2d | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐼  ↦  𝑈 )  ∈  𝐵  ↔  ( 𝑥  ∈  𝐼  ↦  𝑈 )  ∈  X 𝑥  ∈  𝐼 𝐾 ) ) | 
						
							| 9 |  | mptelixpg | ⊢ ( 𝐼  ∈  𝑊  →  ( ( 𝑥  ∈  𝐼  ↦  𝑈 )  ∈  X 𝑥  ∈  𝐼 𝐾  ↔  ∀ 𝑥  ∈  𝐼 𝑈  ∈  𝐾 ) ) | 
						
							| 10 | 4 9 | syl | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐼  ↦  𝑈 )  ∈  X 𝑥  ∈  𝐼 𝐾  ↔  ∀ 𝑥  ∈  𝐼 𝑈  ∈  𝐾 ) ) | 
						
							| 11 | 8 10 | bitrd | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐼  ↦  𝑈 )  ∈  𝐵  ↔  ∀ 𝑥  ∈  𝐼 𝑈  ∈  𝐾 ) ) |