| Step | Hyp | Ref | Expression | 
						
							| 1 |  | suprleubrd.1 | ⊢ ( 𝜑  →  𝐴  ⊆  ℝ ) | 
						
							| 2 |  | suprleubrd.2 | ⊢ ( 𝜑  →  𝐴  ≠  ∅ ) | 
						
							| 3 |  | suprleubrd.3 | ⊢ ( 𝜑  →  ∃ 𝑥  ∈  ℝ ∀ 𝑦  ∈  𝐴 𝑦  ≤  𝑥 ) | 
						
							| 4 |  | suprleubrd.4 | ⊢ ( 𝜑  →  𝐵  ∈  ℝ ) | 
						
							| 5 |  | suprleubrd.5 | ⊢ ( 𝜑  →  ∀ 𝑧  ∈  𝐴 𝑧  ≤  𝐵 ) | 
						
							| 6 |  | suprleub | ⊢ ( ( ( 𝐴  ⊆  ℝ  ∧  𝐴  ≠  ∅  ∧  ∃ 𝑥  ∈  ℝ ∀ 𝑦  ∈  𝐴 𝑦  ≤  𝑥 )  ∧  𝐵  ∈  ℝ )  →  ( sup ( 𝐴 ,  ℝ ,   <  )  ≤  𝐵  ↔  ∀ 𝑧  ∈  𝐴 𝑧  ≤  𝐵 ) ) | 
						
							| 7 | 1 2 3 4 6 | syl31anc | ⊢ ( 𝜑  →  ( sup ( 𝐴 ,  ℝ ,   <  )  ≤  𝐵  ↔  ∀ 𝑧  ∈  𝐴 𝑧  ≤  𝐵 ) ) | 
						
							| 8 | 7 | bicomd | ⊢ ( 𝜑  →  ( ∀ 𝑧  ∈  𝐴 𝑧  ≤  𝐵  ↔  sup ( 𝐴 ,  ℝ ,   <  )  ≤  𝐵 ) ) | 
						
							| 9 | 8 | biimpd | ⊢ ( 𝜑  →  ( ∀ 𝑧  ∈  𝐴 𝑧  ≤  𝐵  →  sup ( 𝐴 ,  ℝ ,   <  )  ≤  𝐵 ) ) | 
						
							| 10 | 9 | imp | ⊢ ( ( 𝜑  ∧  ∀ 𝑧  ∈  𝐴 𝑧  ≤  𝐵 )  →  sup ( 𝐴 ,  ℝ ,   <  )  ≤  𝐵 ) | 
						
							| 11 | 5 10 | mpdan | ⊢ ( 𝜑  →  sup ( 𝐴 ,  ℝ ,   <  )  ≤  𝐵 ) |