| Step | Hyp | Ref | Expression | 
						
							| 1 |  | btwncomand.1 | ⊢ ( 𝜑  →  𝑁  ∈  ℕ ) | 
						
							| 2 |  | btwncomand.2 | ⊢ ( 𝜑  →  𝐴  ∈  ( 𝔼 ‘ 𝑁 ) ) | 
						
							| 3 |  | btwncomand.3 | ⊢ ( 𝜑  →  𝐵  ∈  ( 𝔼 ‘ 𝑁 ) ) | 
						
							| 4 |  | btwncomand.4 | ⊢ ( 𝜑  →  𝐶  ∈  ( 𝔼 ‘ 𝑁 ) ) | 
						
							| 5 |  | btwncomand.5 | ⊢ ( ( 𝜑  ∧  𝜓 )  →  𝐴  Btwn  〈 𝐵 ,  𝐶 〉 ) | 
						
							| 6 |  | btwncom | ⊢ ( ( 𝑁  ∈  ℕ  ∧  ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  ∧  𝐵  ∈  ( 𝔼 ‘ 𝑁 )  ∧  𝐶  ∈  ( 𝔼 ‘ 𝑁 ) ) )  →  ( 𝐴  Btwn  〈 𝐵 ,  𝐶 〉  ↔  𝐴  Btwn  〈 𝐶 ,  𝐵 〉 ) ) | 
						
							| 7 | 1 2 3 4 6 | syl13anc | ⊢ ( 𝜑  →  ( 𝐴  Btwn  〈 𝐵 ,  𝐶 〉  ↔  𝐴  Btwn  〈 𝐶 ,  𝐵 〉 ) ) | 
						
							| 8 | 7 | adantr | ⊢ ( ( 𝜑  ∧  𝜓 )  →  ( 𝐴  Btwn  〈 𝐵 ,  𝐶 〉  ↔  𝐴  Btwn  〈 𝐶 ,  𝐵 〉 ) ) | 
						
							| 9 | 5 8 | mpbid | ⊢ ( ( 𝜑  ∧  𝜓 )  →  𝐴  Btwn  〈 𝐶 ,  𝐵 〉 ) |