| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isprs.b | ⊢ 𝐵  =  ( Base ‘ 𝐾 ) | 
						
							| 2 |  | isprs.l | ⊢  ≤   =  ( le ‘ 𝐾 ) | 
						
							| 3 |  | fveq2 | ⊢ ( 𝑓  =  𝐾  →  ( Base ‘ 𝑓 )  =  ( Base ‘ 𝐾 ) ) | 
						
							| 4 |  | fveq2 | ⊢ ( 𝑓  =  𝐾  →  ( le ‘ 𝑓 )  =  ( le ‘ 𝐾 ) ) | 
						
							| 5 | 4 | sbceq1d | ⊢ ( 𝑓  =  𝐾  →  ( [ ( le ‘ 𝑓 )  /  𝑟 ] ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  [ ( le ‘ 𝐾 )  /  𝑟 ] ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) ) ) ) | 
						
							| 6 | 3 5 | sbceqbid | ⊢ ( 𝑓  =  𝐾  →  ( [ ( Base ‘ 𝑓 )  /  𝑏 ] [ ( le ‘ 𝑓 )  /  𝑟 ] ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  [ ( Base ‘ 𝐾 )  /  𝑏 ] [ ( le ‘ 𝐾 )  /  𝑟 ] ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) ) ) ) | 
						
							| 7 |  | fvex | ⊢ ( Base ‘ 𝐾 )  ∈  V | 
						
							| 8 |  | fvex | ⊢ ( le ‘ 𝐾 )  ∈  V | 
						
							| 9 |  | eqtr3 | ⊢ ( ( 𝑏  =  ( Base ‘ 𝐾 )  ∧  𝐵  =  ( Base ‘ 𝐾 ) )  →  𝑏  =  𝐵 ) | 
						
							| 10 | 1 9 | mpan2 | ⊢ ( 𝑏  =  ( Base ‘ 𝐾 )  →  𝑏  =  𝐵 ) | 
						
							| 11 |  | raleq | ⊢ ( 𝑏  =  𝐵  →  ( ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑧  ∈  𝐵 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) ) ) ) | 
						
							| 12 | 11 | raleqbi1dv | ⊢ ( 𝑏  =  𝐵  →  ( ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) ) ) ) | 
						
							| 13 | 12 | raleqbi1dv | ⊢ ( 𝑏  =  𝐵  →  ( ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) ) ) ) | 
						
							| 14 | 10 13 | syl | ⊢ ( 𝑏  =  ( Base ‘ 𝐾 )  →  ( ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) ) ) ) | 
						
							| 15 |  | eqtr3 | ⊢ ( ( 𝑟  =  ( le ‘ 𝐾 )  ∧   ≤   =  ( le ‘ 𝐾 ) )  →  𝑟  =   ≤  ) | 
						
							| 16 | 2 15 | mpan2 | ⊢ ( 𝑟  =  ( le ‘ 𝐾 )  →  𝑟  =   ≤  ) | 
						
							| 17 |  | breq | ⊢ ( 𝑟  =   ≤   →  ( 𝑥 𝑟 𝑥  ↔  𝑥  ≤  𝑥 ) ) | 
						
							| 18 |  | breq | ⊢ ( 𝑟  =   ≤   →  ( 𝑥 𝑟 𝑦  ↔  𝑥  ≤  𝑦 ) ) | 
						
							| 19 |  | breq | ⊢ ( 𝑟  =   ≤   →  ( 𝑦 𝑟 𝑧  ↔  𝑦  ≤  𝑧 ) ) | 
						
							| 20 | 18 19 | anbi12d | ⊢ ( 𝑟  =   ≤   →  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  ↔  ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 ) ) ) | 
						
							| 21 |  | breq | ⊢ ( 𝑟  =   ≤   →  ( 𝑥 𝑟 𝑧  ↔  𝑥  ≤  𝑧 ) ) | 
						
							| 22 | 20 21 | imbi12d | ⊢ ( 𝑟  =   ≤   →  ( ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 )  ↔  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) | 
						
							| 23 | 17 22 | anbi12d | ⊢ ( 𝑟  =   ≤   →  ( ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) | 
						
							| 24 | 23 | ralbidv | ⊢ ( 𝑟  =   ≤   →  ( ∀ 𝑧  ∈  𝐵 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) | 
						
							| 25 | 24 | 2ralbidv | ⊢ ( 𝑟  =   ≤   →  ( ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) | 
						
							| 26 | 16 25 | syl | ⊢ ( 𝑟  =  ( le ‘ 𝐾 )  →  ( ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) | 
						
							| 27 | 14 26 | sylan9bb | ⊢ ( ( 𝑏  =  ( Base ‘ 𝐾 )  ∧  𝑟  =  ( le ‘ 𝐾 ) )  →  ( ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) | 
						
							| 28 | 7 8 27 | sbc2ie | ⊢ ( [ ( Base ‘ 𝐾 )  /  𝑏 ] [ ( le ‘ 𝐾 )  /  𝑟 ] ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) | 
						
							| 29 | 6 28 | bitrdi | ⊢ ( 𝑓  =  𝐾  →  ( [ ( Base ‘ 𝑓 )  /  𝑏 ] [ ( le ‘ 𝑓 )  /  𝑟 ] ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) | 
						
							| 30 |  | df-proset | ⊢  Proset   =  { 𝑓  ∣  [ ( Base ‘ 𝑓 )  /  𝑏 ] [ ( le ‘ 𝑓 )  /  𝑟 ] ∀ 𝑥  ∈  𝑏 ∀ 𝑦  ∈  𝑏 ∀ 𝑧  ∈  𝑏 ( 𝑥 𝑟 𝑥  ∧  ( ( 𝑥 𝑟 𝑦  ∧  𝑦 𝑟 𝑧 )  →  𝑥 𝑟 𝑧 ) ) } | 
						
							| 31 | 29 30 | elab4g | ⊢ ( 𝐾  ∈   Proset   ↔  ( 𝐾  ∈  V  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ( 𝑥  ≤  𝑥  ∧  ( ( 𝑥  ≤  𝑦  ∧  𝑦  ≤  𝑧 )  →  𝑥  ≤  𝑧 ) ) ) ) |