| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 3oalem1.1 | ⊢ 𝐵  ∈   Cℋ | 
						
							| 2 |  | 3oalem1.2 | ⊢ 𝐶  ∈   Cℋ | 
						
							| 3 |  | 3oalem1.3 | ⊢ 𝑅  ∈   Cℋ | 
						
							| 4 |  | 3oalem1.4 | ⊢ 𝑆  ∈   Cℋ | 
						
							| 5 | 1 | cheli | ⊢ ( 𝑥  ∈  𝐵  →  𝑥  ∈   ℋ ) | 
						
							| 6 | 3 | cheli | ⊢ ( 𝑦  ∈  𝑅  →  𝑦  ∈   ℋ ) | 
						
							| 7 | 5 6 | anim12i | ⊢ ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝑅 )  →  ( 𝑥  ∈   ℋ  ∧  𝑦  ∈   ℋ ) ) | 
						
							| 8 |  | hvaddcl | ⊢ ( ( 𝑥  ∈   ℋ  ∧  𝑦  ∈   ℋ )  →  ( 𝑥  +ℎ  𝑦 )  ∈   ℋ ) | 
						
							| 9 |  | eleq1 | ⊢ ( 𝑣  =  ( 𝑥  +ℎ  𝑦 )  →  ( 𝑣  ∈   ℋ  ↔  ( 𝑥  +ℎ  𝑦 )  ∈   ℋ ) ) | 
						
							| 10 | 8 9 | syl5ibrcom | ⊢ ( ( 𝑥  ∈   ℋ  ∧  𝑦  ∈   ℋ )  →  ( 𝑣  =  ( 𝑥  +ℎ  𝑦 )  →  𝑣  ∈   ℋ ) ) | 
						
							| 11 | 10 | imdistani | ⊢ ( ( ( 𝑥  ∈   ℋ  ∧  𝑦  ∈   ℋ )  ∧  𝑣  =  ( 𝑥  +ℎ  𝑦 ) )  →  ( ( 𝑥  ∈   ℋ  ∧  𝑦  ∈   ℋ )  ∧  𝑣  ∈   ℋ ) ) | 
						
							| 12 | 7 11 | sylan | ⊢ ( ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝑅 )  ∧  𝑣  =  ( 𝑥  +ℎ  𝑦 ) )  →  ( ( 𝑥  ∈   ℋ  ∧  𝑦  ∈   ℋ )  ∧  𝑣  ∈   ℋ ) ) | 
						
							| 13 | 2 | cheli | ⊢ ( 𝑧  ∈  𝐶  →  𝑧  ∈   ℋ ) | 
						
							| 14 | 4 | cheli | ⊢ ( 𝑤  ∈  𝑆  →  𝑤  ∈   ℋ ) | 
						
							| 15 | 13 14 | anim12i | ⊢ ( ( 𝑧  ∈  𝐶  ∧  𝑤  ∈  𝑆 )  →  ( 𝑧  ∈   ℋ  ∧  𝑤  ∈   ℋ ) ) | 
						
							| 16 | 15 | adantr | ⊢ ( ( ( 𝑧  ∈  𝐶  ∧  𝑤  ∈  𝑆 )  ∧  𝑣  =  ( 𝑧  +ℎ  𝑤 ) )  →  ( 𝑧  ∈   ℋ  ∧  𝑤  ∈   ℋ ) ) | 
						
							| 17 | 12 16 | anim12i | ⊢ ( ( ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝑅 )  ∧  𝑣  =  ( 𝑥  +ℎ  𝑦 ) )  ∧  ( ( 𝑧  ∈  𝐶  ∧  𝑤  ∈  𝑆 )  ∧  𝑣  =  ( 𝑧  +ℎ  𝑤 ) ) )  →  ( ( ( 𝑥  ∈   ℋ  ∧  𝑦  ∈   ℋ )  ∧  𝑣  ∈   ℋ )  ∧  ( 𝑧  ∈   ℋ  ∧  𝑤  ∈   ℋ ) ) ) |