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kGonalNodalCurves :: criticalBettiNumberWithoutArtinanReduction

criticalBettiNumberWithoutArtinanReduction -- computes the critical Betti number

Synopsis

Description

Computes the critical Betti number of a canonical curve via Koszul cohomology.

i1 : (k,g,n)=(4,8,1000);
i2 : I=idealOfNodalCurve(k,g,n);

               ZZ
o2 : Ideal of ----[t , t , t , t , t , t , t , t ]
              1009  0   1   2   3   4   5   6   7
i3 : time criticalBettiNumberWithoutArtinanReduction(I)
     -- used 1.68421 seconds

o3 = 4
i4 : time criticalBettiNumberWithoutArtinanReduction(k,g,n)
     -- used 2.47962 seconds

o4 = 4
i5 : betti res I

            0  1  2  3  4  5 6
o5 = total: 1 15 39 50 39 15 1
         0: 1  .  .  .  .  . .
         1: . 15 35 25  4  . .
         2: .  .  4 25 35 15 .
         3: .  .  .  .  .  . 1

o5 : BettiTally

See also

Ways to use criticalBettiNumberWithoutArtinanReduction :

  • criticalBettiNumberWithoutArtinanReduction(Ideal)
  • criticalBettiNumberWithoutArtinanReduction(ZZ,ZZ,ZZ)