# segre(MultiprojectiveVariety) -- the Segre embedding of the variety

## Synopsis

• Function: segre
• Usage:
segre X
• Inputs:
• Outputs:

## Description

 i1 : X = PP_(ZZ/3331)^({2,1,1},{2,1,3}); o1 : ProjectiveVariety, 4-dimensional subvariety of PP^5 x PP^1 x PP^3 i2 : segre X o2 = -- rational map -- ZZ ZZ ZZ source: subvariety of Proj(----[x0 , x0 , x0 , x0 , x0 , x0 ]) x Proj(----[x1 , x1 ]) x Proj(----[x2 , x2 , x2 , x2 ]) defined by 3331 0 1 2 3 4 5 3331 0 1 3331 0 1 2 3 { 2 x2 - x2 x2 , 2 1 3 x2 x2 - x2 x2 , 1 2 0 3 2 x2 - x2 x2 , 1 0 2 2 x0 - x0 x0 , 4 3 5 x0 x0 - x0 x0 , 2 4 1 5 x0 x0 - x0 x0 , 2 3 1 4 2 x0 - x0 x0 , 2 0 5 x0 x0 - x0 x0 , 1 2 0 4 2 x0 - x0 x0 1 0 3 } ZZ target: Proj(----[t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t , t ]) 3331 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 defining forms: { x0 x1 x2 , 0 0 0 x0 x1 x2 , 0 0 1 x0 x1 x2 , 0 0 2 x0 x1 x2 , 0 0 3 x0 x1 x2 , 0 1 0 x0 x1 x2 , 0 1 1 x0 x1 x2 , 0 1 2 x0 x1 x2 , 0 1 3 x0 x1 x2 , 1 0 0 x0 x1 x2 , 1 0 1 x0 x1 x2 , 1 0 2 x0 x1 x2 , 1 0 3 x0 x1 x2 , 1 1 0 x0 x1 x2 , 1 1 1 x0 x1 x2 , 1 1 2 x0 x1 x2 , 1 1 3 x0 x1 x2 , 2 0 0 x0 x1 x2 , 2 0 1 x0 x1 x2 , 2 0 2 x0 x1 x2 , 2 0 3 x0 x1 x2 , 2 1 0 x0 x1 x2 , 2 1 1 x0 x1 x2 , 2 1 2 x0 x1 x2 , 2 1 3 x0 x1 x2 , 3 0 0 x0 x1 x2 , 3 0 1 x0 x1 x2 , 3 0 2 x0 x1 x2 , 3 0 3 x0 x1 x2 , 3 1 0 x0 x1 x2 , 3 1 1 x0 x1 x2 , 3 1 2 x0 x1 x2 , 3 1 3 x0 x1 x2 , 4 0 0 x0 x1 x2 , 4 0 1 x0 x1 x2 , 4 0 2 x0 x1 x2 , 4 0 3 x0 x1 x2 , 4 1 0 x0 x1 x2 , 4 1 1 x0 x1 x2 , 4 1 2 x0 x1 x2 , 4 1 3 x0 x1 x2 , 5 0 0 x0 x1 x2 , 5 0 1 x0 x1 x2 , 5 0 2 x0 x1 x2 , 5 0 3 x0 x1 x2 , 5 1 0 x0 x1 x2 , 5 1 1 x0 x1 x2 , 5 1 2 x0 x1 x2 5 1 3 } o2 : MultihomogeneousRationalMap (rational map from 4-dimensional subvariety of PP^5 x PP^1 x PP^3 to PP^47)