| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isprsd.b | ⊢ ( 𝜑  →  𝐵  =  ( Base ‘ 𝐾 ) ) | 
						
							| 2 |  | isprsd.l | ⊢ ( 𝜑  →   ≤   =  ( le ‘ 𝐾 ) ) | 
						
							| 3 |  | isprsd.k | ⊢ ( 𝜑  →  𝐾  ∈  𝑉 ) | 
						
							| 4 | 3 | elexd | ⊢ ( 𝜑  →  𝐾  ∈  V ) | 
						
							| 5 |  | eqid | ⊢ ( Base ‘ 𝐾 )  =  ( Base ‘ 𝐾 ) | 
						
							| 6 |  | eqid | ⊢ ( le ‘ 𝐾 )  =  ( le ‘ 𝐾 ) | 
						
							| 7 | 5 6 | isprs | ⊢ ( 𝐾  ∈   Proset   ↔  ( 𝐾  ∈  V  ∧  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ∀ 𝑧  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( le ‘ 𝐾 ) 𝑥  ∧  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) ) | 
						
							| 8 | 7 | baib | ⊢ ( 𝐾  ∈  V  →  ( 𝐾  ∈   Proset   ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ∀ 𝑧  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( le ‘ 𝐾 ) 𝑥  ∧  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) ) | 
						
							| 9 | 4 8 | syl | ⊢ ( 𝜑  →  ( 𝐾  ∈   Proset   ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ∀ 𝑧  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( le ‘ 𝐾 ) 𝑥  ∧  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) ) | 
						
							| 10 | 2 | breqd | ⊢ ( 𝜑  →  ( 𝑥  ≤  𝑥  ↔  𝑥 ( le ‘ 𝐾 ) 𝑥 ) ) | 
						
							| 11 | 2 | breqd | ⊢ ( 𝜑  →  ( 𝑥  ≤  𝑦  ↔  𝑥 ( le ‘ 𝐾 ) 𝑦 ) ) | 
						
							| 12 | 2 | breqd | ⊢ ( 𝜑  →  ( 𝑦  ≤  𝑧  ↔  𝑦 ( le ‘ 𝐾 ) 𝑧 ) ) | 
						
							| 13 | 11 12 | anbi12d | ⊢ ( 𝜑  →  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  ↔  ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 ) ) ) | 
						
							| 14 | 2 | breqd | ⊢ ( 𝜑  →  ( 𝑥  ≤  𝑧  ↔  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) | 
						
							| 15 | 13 14 | imbi12d | ⊢ ( 𝜑  →  ( ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 )  ↔  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) | 
						
							| 16 | 10 15 | anbi12d | ⊢ ( 𝜑  →  ( ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) )  ↔  ( 𝑥 ( le ‘ 𝐾 ) 𝑥  ∧  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) ) | 
						
							| 17 | 1 16 | raleqbidv | ⊢ ( 𝜑  →  ( ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) )  ↔  ∀ 𝑧  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( le ‘ 𝐾 ) 𝑥  ∧  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) ) | 
						
							| 18 | 1 17 | raleqbidv | ⊢ ( 𝜑  →  ( ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) )  ↔  ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ∀ 𝑧  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( le ‘ 𝐾 ) 𝑥  ∧  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) ) | 
						
							| 19 | 1 18 | raleqbidv | ⊢ ( 𝜑  →  ( ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) )  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ∀ 𝑧  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( le ‘ 𝐾 ) 𝑥  ∧  ( ( 𝑥 ( le ‘ 𝐾 ) 𝑦  ∧  𝑦 ( le ‘ 𝐾 ) 𝑧 )  →  𝑥 ( le ‘ 𝐾 ) 𝑧 ) ) ) ) | 
						
							| 20 | 9 19 | bitr4d | ⊢ ( 𝜑  →  ( 𝐾  ∈   Proset   ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) |