Quelle  varieties_segre.include  Sprache: unbekannt

gap>; sv:=SegreVariety(2,2,9);
Segre Variety in ProjectiveSpace(8, 9)
gap>; sm:=SegreMap(sv);
Segre Map of [ <;points of ProjectiveSpace(2, 9)>, 
  <;points of ProjectiveSpace(2, 9)> ]
gap>; cart1:=Cartesian(Points(PG(2,9)),Points(PG(2,9)));;
gap>; im1:=ImagesSet(sm,cart1);;
gap>; Span(im1);
ProjectiveSpace(8, 9)
gap>; l:=Random(Lines(PG(2,9)));
<;a line in ProjectiveSpace(2, 9)>
gap>; cart2:=Cartesian(Points(l),Points(PG(2,9)));;
gap>; im2:=ImagesSet(sm,cart2);;
gap>; Span(im2);
<;a proj. 5-space in ProjectiveSpace(8, 9)>
gap>; x:=Random(Points(PG(2,9)));
<;a point in ProjectiveSpace(2, 9)>
gap>; cart3:=Cartesian(Points(PG(2,9)),Points(x));;
gap>; im3:=ImagesSet(sm,cart3);;
gap>; pi:=Span(im3);
<;a plane in ProjectiveSpace(8, 9)>
gap>; AsSet(List(Points(pi),y->y in sv));
[ true ]