| Step | Hyp | Ref | Expression | 
						
							| 1 |  | brsegle |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( <. A , B >. Seg<_ <. C , D >. <-> E. y e. ( EE ` N ) ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) ) ) | 
						
							| 2 |  | brsegle2 |  |-  ( ( N e. NN /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) ) -> ( <. C , D >. Seg<_ <. A , B >. <-> E. t e. ( EE ` N ) ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) | 
						
							| 3 | 2 | 3com23 |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( <. C , D >. Seg<_ <. A , B >. <-> E. t e. ( EE ` N ) ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) | 
						
							| 4 | 1 3 | anbi12d |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( ( <. A , B >. Seg<_ <. C , D >. /\ <. C , D >. Seg<_ <. A , B >. ) <-> ( E. y e. ( EE ` N ) ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ E. t e. ( EE ` N ) ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) ) | 
						
							| 5 |  | reeanv |  |-  ( E. y e. ( EE ` N ) E. t e. ( EE ` N ) ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) <-> ( E. y e. ( EE ` N ) ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ E. t e. ( EE ` N ) ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) | 
						
							| 6 | 4 5 | bitr4di |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( ( <. A , B >. Seg<_ <. C , D >. /\ <. C , D >. Seg<_ <. A , B >. ) <-> E. y e. ( EE ` N ) E. t e. ( EE ` N ) ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) ) | 
						
							| 7 |  | simpl1 |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> N e. NN ) | 
						
							| 8 |  | simpl3l |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> C e. ( EE ` N ) ) | 
						
							| 9 |  | simprr |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> t e. ( EE ` N ) ) | 
						
							| 10 |  | simprl |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> y e. ( EE ` N ) ) | 
						
							| 11 |  | simpl3r |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> D e. ( EE ` N ) ) | 
						
							| 12 |  | simprll |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> y Btwn <. C , D >. ) | 
						
							| 13 |  | simprrl |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> D Btwn <. C , t >. ) | 
						
							| 14 | 7 8 10 11 9 12 13 | btwnexchand |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> y Btwn <. C , t >. ) | 
						
							| 15 |  | simpl2l |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> A e. ( EE ` N ) ) | 
						
							| 16 |  | simpl2r |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> B e. ( EE ` N ) ) | 
						
							| 17 |  | simprrr |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> <. C , t >. Cgr <. A , B >. ) | 
						
							| 18 |  | simprlr |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> <. A , B >. Cgr <. C , y >. ) | 
						
							| 19 | 7 8 9 15 16 8 10 17 18 | cgrtrand |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> <. C , t >. Cgr <. C , y >. ) | 
						
							| 20 | 7 8 9 10 14 19 | endofsegidand |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> t = y ) | 
						
							| 21 |  | opeq2 |  |-  ( t = y -> <. C , t >. = <. C , y >. ) | 
						
							| 22 | 21 | breq2d |  |-  ( t = y -> ( D Btwn <. C , t >. <-> D Btwn <. C , y >. ) ) | 
						
							| 23 | 21 | breq1d |  |-  ( t = y -> ( <. C , t >. Cgr <. A , B >. <-> <. C , y >. Cgr <. A , B >. ) ) | 
						
							| 24 | 22 23 | anbi12d |  |-  ( t = y -> ( ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) <-> ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) | 
						
							| 25 | 24 | anbi2d |  |-  ( t = y -> ( ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) <-> ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) ) | 
						
							| 26 | 25 | anbi2d |  |-  ( t = y -> ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) <-> ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) ) ) | 
						
							| 27 |  | simprrl |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> D Btwn <. C , y >. ) | 
						
							| 28 | 7 11 8 10 27 | btwncomand |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> D Btwn <. y , C >. ) | 
						
							| 29 |  | simprll |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> y Btwn <. C , D >. ) | 
						
							| 30 | 7 10 8 11 29 | btwncomand |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> y Btwn <. D , C >. ) | 
						
							| 31 |  | btwnswapid |  |-  ( ( N e. NN /\ ( D e. ( EE ` N ) /\ y e. ( EE ` N ) /\ C e. ( EE ` N ) ) ) -> ( ( D Btwn <. y , C >. /\ y Btwn <. D , C >. ) -> D = y ) ) | 
						
							| 32 | 7 11 10 8 31 | syl13anc |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) -> ( ( D Btwn <. y , C >. /\ y Btwn <. D , C >. ) -> D = y ) ) | 
						
							| 33 | 32 | adantr |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> ( ( D Btwn <. y , C >. /\ y Btwn <. D , C >. ) -> D = y ) ) | 
						
							| 34 | 28 30 33 | mp2and |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> D = y ) | 
						
							| 35 |  | simprlr |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> <. A , B >. Cgr <. C , y >. ) | 
						
							| 36 |  | opeq2 |  |-  ( D = y -> <. C , D >. = <. C , y >. ) | 
						
							| 37 | 36 | breq2d |  |-  ( D = y -> ( <. A , B >. Cgr <. C , D >. <-> <. A , B >. Cgr <. C , y >. ) ) | 
						
							| 38 | 35 37 | syl5ibrcom |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> ( D = y -> <. A , B >. Cgr <. C , D >. ) ) | 
						
							| 39 | 34 38 | mpd |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , y >. /\ <. C , y >. Cgr <. A , B >. ) ) ) -> <. A , B >. Cgr <. C , D >. ) | 
						
							| 40 | 26 39 | biimtrdi |  |-  ( t = y -> ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> <. A , B >. Cgr <. C , D >. ) ) | 
						
							| 41 | 20 40 | mpcom |  |-  ( ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) ) /\ ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) ) -> <. A , B >. Cgr <. C , D >. ) | 
						
							| 42 | 41 | exp31 |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( ( y e. ( EE ` N ) /\ t e. ( EE ` N ) ) -> ( ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) -> <. A , B >. Cgr <. C , D >. ) ) ) | 
						
							| 43 | 42 | rexlimdvv |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( E. y e. ( EE ` N ) E. t e. ( EE ` N ) ( ( y Btwn <. C , D >. /\ <. A , B >. Cgr <. C , y >. ) /\ ( D Btwn <. C , t >. /\ <. C , t >. Cgr <. A , B >. ) ) -> <. A , B >. Cgr <. C , D >. ) ) | 
						
							| 44 | 6 43 | sylbid |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( ( <. A , B >. Seg<_ <. C , D >. /\ <. C , D >. Seg<_ <. A , B >. ) -> <. A , B >. Cgr <. C , D >. ) ) |