| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ixx.1 |  |-  O = ( x e. RR* , y e. RR* |-> { z e. RR* | ( x R z /\ z S y ) } ) | 
						
							| 2 |  | ixxss12.2 |  |-  P = ( x e. RR* , y e. RR* |-> { z e. RR* | ( x T z /\ z U y ) } ) | 
						
							| 3 |  | ixxss12.3 |  |-  ( ( A e. RR* /\ C e. RR* /\ w e. RR* ) -> ( ( A W C /\ C T w ) -> A R w ) ) | 
						
							| 4 |  | ixxss12.4 |  |-  ( ( w e. RR* /\ D e. RR* /\ B e. RR* ) -> ( ( w U D /\ D X B ) -> w S B ) ) | 
						
							| 5 | 2 | elixx3g |  |-  ( w e. ( C P D ) <-> ( ( C e. RR* /\ D e. RR* /\ w e. RR* ) /\ ( C T w /\ w U D ) ) ) | 
						
							| 6 | 5 | simplbi |  |-  ( w e. ( C P D ) -> ( C e. RR* /\ D e. RR* /\ w e. RR* ) ) | 
						
							| 7 | 6 | adantl |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> ( C e. RR* /\ D e. RR* /\ w e. RR* ) ) | 
						
							| 8 | 7 | simp3d |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> w e. RR* ) | 
						
							| 9 |  | simplrl |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> A W C ) | 
						
							| 10 | 5 | simprbi |  |-  ( w e. ( C P D ) -> ( C T w /\ w U D ) ) | 
						
							| 11 | 10 | adantl |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> ( C T w /\ w U D ) ) | 
						
							| 12 | 11 | simpld |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> C T w ) | 
						
							| 13 |  | simplll |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> A e. RR* ) | 
						
							| 14 | 7 | simp1d |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> C e. RR* ) | 
						
							| 15 | 13 14 8 3 | syl3anc |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> ( ( A W C /\ C T w ) -> A R w ) ) | 
						
							| 16 | 9 12 15 | mp2and |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> A R w ) | 
						
							| 17 | 11 | simprd |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> w U D ) | 
						
							| 18 |  | simplrr |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> D X B ) | 
						
							| 19 | 7 | simp2d |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> D e. RR* ) | 
						
							| 20 |  | simpllr |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> B e. RR* ) | 
						
							| 21 | 8 19 20 4 | syl3anc |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> ( ( w U D /\ D X B ) -> w S B ) ) | 
						
							| 22 | 17 18 21 | mp2and |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> w S B ) | 
						
							| 23 | 1 | elixx1 |  |-  ( ( A e. RR* /\ B e. RR* ) -> ( w e. ( A O B ) <-> ( w e. RR* /\ A R w /\ w S B ) ) ) | 
						
							| 24 | 23 | ad2antrr |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> ( w e. ( A O B ) <-> ( w e. RR* /\ A R w /\ w S B ) ) ) | 
						
							| 25 | 8 16 22 24 | mpbir3and |  |-  ( ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) /\ w e. ( C P D ) ) -> w e. ( A O B ) ) | 
						
							| 26 | 25 | ex |  |-  ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) -> ( w e. ( C P D ) -> w e. ( A O B ) ) ) | 
						
							| 27 | 26 | ssrdv |  |-  ( ( ( A e. RR* /\ B e. RR* ) /\ ( A W C /\ D X B ) ) -> ( C P D ) C_ ( A O B ) ) |