| Step | Hyp | Ref | Expression | 
						
							| 1 |  | tosso.b | ⊢ 𝐵  =  ( Base ‘ 𝐾 ) | 
						
							| 2 |  | tosso.l | ⊢  ≤   =  ( le ‘ 𝐾 ) | 
						
							| 3 |  | tosso.s | ⊢  <   =  ( lt ‘ 𝐾 ) | 
						
							| 4 | 1 2 3 | pleval2 | ⊢ ( ( 𝐾  ∈  Poset  ∧  𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  →  ( 𝑥  ≤  𝑦  ↔  ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 5 | 4 | 3expb | ⊢ ( ( 𝐾  ∈  Poset  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( 𝑥  ≤  𝑦  ↔  ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 6 | 1 2 3 | pleval2 | ⊢ ( ( 𝐾  ∈  Poset  ∧  𝑦  ∈  𝐵  ∧  𝑥  ∈  𝐵 )  →  ( 𝑦  ≤  𝑥  ↔  ( 𝑦  <  𝑥  ∨  𝑦  =  𝑥 ) ) ) | 
						
							| 7 |  | equcom | ⊢ ( 𝑦  =  𝑥  ↔  𝑥  =  𝑦 ) | 
						
							| 8 | 7 | orbi2i | ⊢ ( ( 𝑦  <  𝑥  ∨  𝑦  =  𝑥 )  ↔  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 9 | 6 8 | bitrdi | ⊢ ( ( 𝐾  ∈  Poset  ∧  𝑦  ∈  𝐵  ∧  𝑥  ∈  𝐵 )  →  ( 𝑦  ≤  𝑥  ↔  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 10 | 9 | 3com23 | ⊢ ( ( 𝐾  ∈  Poset  ∧  𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  →  ( 𝑦  ≤  𝑥  ↔  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 11 | 10 | 3expb | ⊢ ( ( 𝐾  ∈  Poset  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( 𝑦  ≤  𝑥  ↔  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 12 | 5 11 | orbi12d | ⊢ ( ( 𝐾  ∈  Poset  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( ( 𝑥  ≤  𝑦  ∨  𝑦  ≤  𝑥 )  ↔  ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 )  ∨  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) ) ) | 
						
							| 13 |  | df-3or | ⊢ ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 )  ↔  ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 )  ∨  𝑦  <  𝑥 ) ) | 
						
							| 14 |  | or32 | ⊢ ( ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 )  ∨  𝑦  <  𝑥 )  ↔  ( ( 𝑥  <  𝑦  ∨  𝑦  <  𝑥 )  ∨  𝑥  =  𝑦 ) ) | 
						
							| 15 |  | orordir | ⊢ ( ( ( 𝑥  <  𝑦  ∨  𝑦  <  𝑥 )  ∨  𝑥  =  𝑦 )  ↔  ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 )  ∨  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 16 | 14 15 | bitri | ⊢ ( ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 )  ∨  𝑦  <  𝑥 )  ↔  ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 )  ∨  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 17 | 13 16 | bitri | ⊢ ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 )  ↔  ( ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦 )  ∨  ( 𝑦  <  𝑥  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 18 | 12 17 | bitr4di | ⊢ ( ( 𝐾  ∈  Poset  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( ( 𝑥  ≤  𝑦  ∨  𝑦  ≤  𝑥 )  ↔  ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) | 
						
							| 19 | 18 | 2ralbidva | ⊢ ( 𝐾  ∈  Poset  →  ( ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  ≤  𝑦  ∨  𝑦  ≤  𝑥 )  ↔  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) | 
						
							| 20 | 19 | pm5.32i | ⊢ ( ( 𝐾  ∈  Poset  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  ≤  𝑦  ∨  𝑦  ≤  𝑥 ) )  ↔  ( 𝐾  ∈  Poset  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) | 
						
							| 21 | 1 2 3 | pospo | ⊢ ( 𝐾  ∈  𝑉  →  ( 𝐾  ∈  Poset  ↔  (  <   Po  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  ) ) ) | 
						
							| 22 | 21 | anbi1d | ⊢ ( 𝐾  ∈  𝑉  →  ( ( 𝐾  ∈  Poset  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) )  ↔  ( (  <   Po  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  )  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) ) | 
						
							| 23 | 20 22 | bitrid | ⊢ ( 𝐾  ∈  𝑉  →  ( ( 𝐾  ∈  Poset  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  ≤  𝑦  ∨  𝑦  ≤  𝑥 ) )  ↔  ( (  <   Po  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  )  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) ) | 
						
							| 24 | 1 2 | istos | ⊢ ( 𝐾  ∈  Toset  ↔  ( 𝐾  ∈  Poset  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  ≤  𝑦  ∨  𝑦  ≤  𝑥 ) ) ) | 
						
							| 25 |  | df-so | ⊢ (  <   Or  𝐵  ↔  (  <   Po  𝐵  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) | 
						
							| 26 | 25 | anbi1i | ⊢ ( (  <   Or  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  )  ↔  ( (  <   Po  𝐵  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) )  ∧  (  I   ↾  𝐵 )  ⊆   ≤  ) ) | 
						
							| 27 |  | an32 | ⊢ ( ( (  <   Po  𝐵  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) )  ∧  (  I   ↾  𝐵 )  ⊆   ≤  )  ↔  ( (  <   Po  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  )  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) | 
						
							| 28 | 26 27 | bitri | ⊢ ( (  <   Or  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  )  ↔  ( (  <   Po  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  )  ∧  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ( 𝑥  <  𝑦  ∨  𝑥  =  𝑦  ∨  𝑦  <  𝑥 ) ) ) | 
						
							| 29 | 23 24 28 | 3bitr4g | ⊢ ( 𝐾  ∈  𝑉  →  ( 𝐾  ∈  Toset  ↔  (  <   Or  𝐵  ∧  (  I   ↾  𝐵 )  ⊆   ≤  ) ) ) |