| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ceqsex6v.1 | ⊢ 𝐴  ∈  V | 
						
							| 2 |  | ceqsex6v.2 | ⊢ 𝐵  ∈  V | 
						
							| 3 |  | ceqsex6v.3 | ⊢ 𝐶  ∈  V | 
						
							| 4 |  | ceqsex6v.4 | ⊢ 𝐷  ∈  V | 
						
							| 5 |  | ceqsex6v.5 | ⊢ 𝐸  ∈  V | 
						
							| 6 |  | ceqsex6v.6 | ⊢ 𝐹  ∈  V | 
						
							| 7 |  | ceqsex6v.7 | ⊢ ( 𝑥  =  𝐴  →  ( 𝜑  ↔  𝜓 ) ) | 
						
							| 8 |  | ceqsex6v.8 | ⊢ ( 𝑦  =  𝐵  →  ( 𝜓  ↔  𝜒 ) ) | 
						
							| 9 |  | ceqsex6v.9 | ⊢ ( 𝑧  =  𝐶  →  ( 𝜒  ↔  𝜃 ) ) | 
						
							| 10 |  | ceqsex6v.10 | ⊢ ( 𝑤  =  𝐷  →  ( 𝜃  ↔  𝜏 ) ) | 
						
							| 11 |  | ceqsex6v.11 | ⊢ ( 𝑣  =  𝐸  →  ( 𝜏  ↔  𝜂 ) ) | 
						
							| 12 |  | ceqsex6v.12 | ⊢ ( 𝑢  =  𝐹  →  ( 𝜂  ↔  𝜁 ) ) | 
						
							| 13 |  | 3anass | ⊢ ( ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 )  ↔  ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 ) ) ) | 
						
							| 14 | 13 | 3exbii | ⊢ ( ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 )  ↔  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 ) ) ) | 
						
							| 15 |  | 19.42vvv | ⊢ ( ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 ) )  ↔  ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 ) ) ) | 
						
							| 16 | 14 15 | bitri | ⊢ ( ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 )  ↔  ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 ) ) ) | 
						
							| 17 | 16 | 3exbii | ⊢ ( ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 )  ↔  ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 ) ) ) | 
						
							| 18 | 7 | anbi2d | ⊢ ( 𝑥  =  𝐴  →  ( ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 )  ↔  ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜓 ) ) ) | 
						
							| 19 | 18 | 3exbidv | ⊢ ( 𝑥  =  𝐴  →  ( ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 )  ↔  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜓 ) ) ) | 
						
							| 20 | 8 | anbi2d | ⊢ ( 𝑦  =  𝐵  →  ( ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜓 )  ↔  ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜒 ) ) ) | 
						
							| 21 | 20 | 3exbidv | ⊢ ( 𝑦  =  𝐵  →  ( ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜓 )  ↔  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜒 ) ) ) | 
						
							| 22 | 9 | anbi2d | ⊢ ( 𝑧  =  𝐶  →  ( ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜒 )  ↔  ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜃 ) ) ) | 
						
							| 23 | 22 | 3exbidv | ⊢ ( 𝑧  =  𝐶  →  ( ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜒 )  ↔  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜃 ) ) ) | 
						
							| 24 | 1 2 3 19 21 23 | ceqsex3v | ⊢ ( ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 ) )  ↔  ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜃 ) ) | 
						
							| 25 | 4 5 6 10 11 12 | ceqsex3v | ⊢ ( ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜃 )  ↔  𝜁 ) | 
						
							| 26 | 17 24 25 | 3bitri | ⊢ ( ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ∃ 𝑤 ∃ 𝑣 ∃ 𝑢 ( ( 𝑥  =  𝐴  ∧  𝑦  =  𝐵  ∧  𝑧  =  𝐶 )  ∧  ( 𝑤  =  𝐷  ∧  𝑣  =  𝐸  ∧  𝑢  =  𝐹 )  ∧  𝜑 )  ↔  𝜁 ) |