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MultiprojectiveVarieties :: point(MultiprojectiveVariety)

point(MultiprojectiveVariety) -- pick a random rational point on a multi-projective variety

Synopsis

Description

i1 : K = ZZ/1000003;
i2 : X = PP_K^({1,1,2},{3,2,3});

o2 : ProjectiveVariety, 4-dimensional subvariety of PP^3 x PP^2 x PP^9
i3 : time p := point X
     -- used 0.0484723 seconds

o3 = point of coordinates ([421369, 39917, -212481, 1],[-128795, -176966, 1],[3870, -390108, -496127, -308581, 46649, 164926, -446111, 48038, 415309, 1])

o3 : ProjectiveVariety, a point in PP^3 x PP^2 x PP^9
i4 : Y = random({2,1,2},X);

o4 : ProjectiveVariety, hypersurface in PP^3 x PP^2 x PP^9
i5 : time q = point Y
     -- used 0.814212 seconds

o5 = q

o5 : ProjectiveVariety, a point in PP^3 x PP^2 x PP^9
i6 : assert(isSubset(p,X) and isSubset(q,Y))

The list of homogeneous coordinates can be obtained with the operator |-.

i7 : |- p

o7 = ([421369, 39917, -212481, 1], [-128795, -176966, 1], [3870, -390108,
     ------------------------------------------------------------------------
     -496127, -308581, 46649, 164926, -446111, 48038, 415309, 1])

o7 : Sequence
i8 : |- q

o8 = ([-122098, -220812, 33092, 1], [395730, 340415, 1], [177496, -288667,
     ------------------------------------------------------------------------
     250341, 392818, -498075, 14832, 97109, -330219, 201194, 1])

o8 : Sequence

See also