| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cntzrcl.b | ⊢ 𝐵  =  ( Base ‘ 𝑀 ) | 
						
							| 2 |  | cntzrcl.z | ⊢ 𝑍  =  ( Cntz ‘ 𝑀 ) | 
						
							| 3 |  | 0ss | ⊢ ∅  ⊆  𝐵 | 
						
							| 4 |  | sseq1 | ⊢ ( ( 𝑍 ‘ 𝑆 )  =  ∅  →  ( ( 𝑍 ‘ 𝑆 )  ⊆  𝐵  ↔  ∅  ⊆  𝐵 ) ) | 
						
							| 5 | 3 4 | mpbiri | ⊢ ( ( 𝑍 ‘ 𝑆 )  =  ∅  →  ( 𝑍 ‘ 𝑆 )  ⊆  𝐵 ) | 
						
							| 6 |  | n0 | ⊢ ( ( 𝑍 ‘ 𝑆 )  ≠  ∅  ↔  ∃ 𝑥 𝑥  ∈  ( 𝑍 ‘ 𝑆 ) ) | 
						
							| 7 | 1 2 | cntzrcl | ⊢ ( 𝑥  ∈  ( 𝑍 ‘ 𝑆 )  →  ( 𝑀  ∈  V  ∧  𝑆  ⊆  𝐵 ) ) | 
						
							| 8 |  | eqid | ⊢ ( +g ‘ 𝑀 )  =  ( +g ‘ 𝑀 ) | 
						
							| 9 | 1 8 2 | cntzval | ⊢ ( 𝑆  ⊆  𝐵  →  ( 𝑍 ‘ 𝑆 )  =  { 𝑥  ∈  𝐵  ∣  ∀ 𝑦  ∈  𝑆 ( 𝑥 ( +g ‘ 𝑀 ) 𝑦 )  =  ( 𝑦 ( +g ‘ 𝑀 ) 𝑥 ) } ) | 
						
							| 10 | 7 9 | simpl2im | ⊢ ( 𝑥  ∈  ( 𝑍 ‘ 𝑆 )  →  ( 𝑍 ‘ 𝑆 )  =  { 𝑥  ∈  𝐵  ∣  ∀ 𝑦  ∈  𝑆 ( 𝑥 ( +g ‘ 𝑀 ) 𝑦 )  =  ( 𝑦 ( +g ‘ 𝑀 ) 𝑥 ) } ) | 
						
							| 11 |  | ssrab2 | ⊢ { 𝑥  ∈  𝐵  ∣  ∀ 𝑦  ∈  𝑆 ( 𝑥 ( +g ‘ 𝑀 ) 𝑦 )  =  ( 𝑦 ( +g ‘ 𝑀 ) 𝑥 ) }  ⊆  𝐵 | 
						
							| 12 | 10 11 | eqsstrdi | ⊢ ( 𝑥  ∈  ( 𝑍 ‘ 𝑆 )  →  ( 𝑍 ‘ 𝑆 )  ⊆  𝐵 ) | 
						
							| 13 | 12 | exlimiv | ⊢ ( ∃ 𝑥 𝑥  ∈  ( 𝑍 ‘ 𝑆 )  →  ( 𝑍 ‘ 𝑆 )  ⊆  𝐵 ) | 
						
							| 14 | 6 13 | sylbi | ⊢ ( ( 𝑍 ‘ 𝑆 )  ≠  ∅  →  ( 𝑍 ‘ 𝑆 )  ⊆  𝐵 ) | 
						
							| 15 | 5 14 | pm2.61ine | ⊢ ( 𝑍 ‘ 𝑆 )  ⊆  𝐵 |