| Step | Hyp | Ref | Expression | 
						
							| 1 |  | srgfcl.b |  |-  B = ( Base ` R ) | 
						
							| 2 |  | srgfcl.t |  |-  .x. = ( .r ` R ) | 
						
							| 3 |  | simpr |  |-  ( ( R e. SRing /\ .x. Fn ( B X. B ) ) -> .x. Fn ( B X. B ) ) | 
						
							| 4 | 1 2 | srgcl |  |-  ( ( R e. SRing /\ a e. B /\ b e. B ) -> ( a .x. b ) e. B ) | 
						
							| 5 | 4 | 3expb |  |-  ( ( R e. SRing /\ ( a e. B /\ b e. B ) ) -> ( a .x. b ) e. B ) | 
						
							| 6 | 5 | ralrimivva |  |-  ( R e. SRing -> A. a e. B A. b e. B ( a .x. b ) e. B ) | 
						
							| 7 |  | fveq2 |  |-  ( c = <. a , b >. -> ( .x. ` c ) = ( .x. ` <. a , b >. ) ) | 
						
							| 8 | 7 | eleq1d |  |-  ( c = <. a , b >. -> ( ( .x. ` c ) e. B <-> ( .x. ` <. a , b >. ) e. B ) ) | 
						
							| 9 |  | df-ov |  |-  ( a .x. b ) = ( .x. ` <. a , b >. ) | 
						
							| 10 | 9 | eqcomi |  |-  ( .x. ` <. a , b >. ) = ( a .x. b ) | 
						
							| 11 | 10 | eleq1i |  |-  ( ( .x. ` <. a , b >. ) e. B <-> ( a .x. b ) e. B ) | 
						
							| 12 | 8 11 | bitrdi |  |-  ( c = <. a , b >. -> ( ( .x. ` c ) e. B <-> ( a .x. b ) e. B ) ) | 
						
							| 13 | 12 | ralxp |  |-  ( A. c e. ( B X. B ) ( .x. ` c ) e. B <-> A. a e. B A. b e. B ( a .x. b ) e. B ) | 
						
							| 14 | 6 13 | sylibr |  |-  ( R e. SRing -> A. c e. ( B X. B ) ( .x. ` c ) e. B ) | 
						
							| 15 | 14 | adantr |  |-  ( ( R e. SRing /\ .x. Fn ( B X. B ) ) -> A. c e. ( B X. B ) ( .x. ` c ) e. B ) | 
						
							| 16 |  | fnfvrnss |  |-  ( ( .x. Fn ( B X. B ) /\ A. c e. ( B X. B ) ( .x. ` c ) e. B ) -> ran .x. C_ B ) | 
						
							| 17 | 3 15 16 | syl2anc |  |-  ( ( R e. SRing /\ .x. Fn ( B X. B ) ) -> ran .x. C_ B ) | 
						
							| 18 |  | df-f |  |-  ( .x. : ( B X. B ) --> B <-> ( .x. Fn ( B X. B ) /\ ran .x. C_ B ) ) | 
						
							| 19 | 3 17 18 | sylanbrc |  |-  ( ( R e. SRing /\ .x. Fn ( B X. B ) ) -> .x. : ( B X. B ) --> B ) |