| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eleei |  |-  ( A e. ( EE ` N ) -> A : ( 1 ... N ) --> RR ) | 
						
							| 2 |  | eleei |  |-  ( A e. ( EE ` M ) -> A : ( 1 ... M ) --> RR ) | 
						
							| 3 |  | fdm |  |-  ( A : ( 1 ... N ) --> RR -> dom A = ( 1 ... N ) ) | 
						
							| 4 |  | fdm |  |-  ( A : ( 1 ... M ) --> RR -> dom A = ( 1 ... M ) ) | 
						
							| 5 | 3 4 | sylan9req |  |-  ( ( A : ( 1 ... N ) --> RR /\ A : ( 1 ... M ) --> RR ) -> ( 1 ... N ) = ( 1 ... M ) ) | 
						
							| 6 | 1 2 5 | syl2an |  |-  ( ( A e. ( EE ` N ) /\ A e. ( EE ` M ) ) -> ( 1 ... N ) = ( 1 ... M ) ) | 
						
							| 7 |  | eleenn |  |-  ( A e. ( EE ` N ) -> N e. NN ) | 
						
							| 8 |  | nnuz |  |-  NN = ( ZZ>= ` 1 ) | 
						
							| 9 | 7 8 | eleqtrdi |  |-  ( A e. ( EE ` N ) -> N e. ( ZZ>= ` 1 ) ) | 
						
							| 10 | 9 | adantr |  |-  ( ( A e. ( EE ` N ) /\ A e. ( EE ` M ) ) -> N e. ( ZZ>= ` 1 ) ) | 
						
							| 11 |  | fzopth |  |-  ( N e. ( ZZ>= ` 1 ) -> ( ( 1 ... N ) = ( 1 ... M ) <-> ( 1 = 1 /\ N = M ) ) ) | 
						
							| 12 | 10 11 | syl |  |-  ( ( A e. ( EE ` N ) /\ A e. ( EE ` M ) ) -> ( ( 1 ... N ) = ( 1 ... M ) <-> ( 1 = 1 /\ N = M ) ) ) | 
						
							| 13 | 6 12 | mpbid |  |-  ( ( A e. ( EE ` N ) /\ A e. ( EE ` M ) ) -> ( 1 = 1 /\ N = M ) ) | 
						
							| 14 | 13 | simprd |  |-  ( ( A e. ( EE ` N ) /\ A e. ( EE ` M ) ) -> N = M ) |