| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-colinear |  |-  Colinear = `' { <. <. b , c >. , a >. | E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) } | 
						
							| 2 |  | nnex |  |-  NN e. _V | 
						
							| 3 |  | fvex |  |-  ( EE ` n ) e. _V | 
						
							| 4 | 3 3 | xpex |  |-  ( ( EE ` n ) X. ( EE ` n ) ) e. _V | 
						
							| 5 | 4 3 | xpex |  |-  ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) e. _V | 
						
							| 6 | 2 5 | iunex |  |-  U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) e. _V | 
						
							| 7 |  | df-oprab |  |-  { <. <. b , c >. , a >. | E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) } = { x | E. b E. c E. a ( x = <. <. b , c >. , a >. /\ E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) ) } | 
						
							| 8 |  | opelxpi |  |-  ( ( b e. ( EE ` n ) /\ c e. ( EE ` n ) ) -> <. b , c >. e. ( ( EE ` n ) X. ( EE ` n ) ) ) | 
						
							| 9 | 8 | 3adant1 |  |-  ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) -> <. b , c >. e. ( ( EE ` n ) X. ( EE ` n ) ) ) | 
						
							| 10 |  | simp1 |  |-  ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) -> a e. ( EE ` n ) ) | 
						
							| 11 |  | opelxpi |  |-  ( ( <. b , c >. e. ( ( EE ` n ) X. ( EE ` n ) ) /\ a e. ( EE ` n ) ) -> <. <. b , c >. , a >. e. ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 12 | 9 10 11 | syl2anc |  |-  ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) -> <. <. b , c >. , a >. e. ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 13 | 12 | adantr |  |-  ( ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) -> <. <. b , c >. , a >. e. ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 14 | 13 | reximi |  |-  ( E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) -> E. n e. NN <. <. b , c >. , a >. e. ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 15 |  | eliun |  |-  ( <. <. b , c >. , a >. e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) <-> E. n e. NN <. <. b , c >. , a >. e. ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 16 | 14 15 | sylibr |  |-  ( E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) -> <. <. b , c >. , a >. e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 17 |  | eleq1 |  |-  ( x = <. <. b , c >. , a >. -> ( x e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) <-> <. <. b , c >. , a >. e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) ) | 
						
							| 18 | 17 | biimpar |  |-  ( ( x = <. <. b , c >. , a >. /\ <. <. b , c >. , a >. e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) -> x e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 19 | 16 18 | sylan2 |  |-  ( ( x = <. <. b , c >. , a >. /\ E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) ) -> x e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 20 | 19 | exlimiv |  |-  ( E. a ( x = <. <. b , c >. , a >. /\ E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) ) -> x e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 21 | 20 | exlimivv |  |-  ( E. b E. c E. a ( x = <. <. b , c >. , a >. /\ E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) ) -> x e. U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) ) | 
						
							| 22 | 21 | abssi |  |-  { x | E. b E. c E. a ( x = <. <. b , c >. , a >. /\ E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) ) } C_ U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) | 
						
							| 23 | 7 22 | eqsstri |  |-  { <. <. b , c >. , a >. | E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) } C_ U_ n e. NN ( ( ( EE ` n ) X. ( EE ` n ) ) X. ( EE ` n ) ) | 
						
							| 24 | 6 23 | ssexi |  |-  { <. <. b , c >. , a >. | E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) } e. _V | 
						
							| 25 | 24 | cnvex |  |-  `' { <. <. b , c >. , a >. | E. n e. NN ( ( a e. ( EE ` n ) /\ b e. ( EE ` n ) /\ c e. ( EE ` n ) ) /\ ( a Btwn <. b , c >. \/ b Btwn <. c , a >. \/ c Btwn <. a , b >. ) ) } e. _V | 
						
							| 26 | 1 25 | eqeltri |  |-  Colinear e. _V |