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nonWeierstrassSemigroups -- Find possibly non Weierstrass Semigroups

Synopsis

Description

We test which semigroups of multiplicity m and genus g are smoothable. If no smoothing was found then L is a candidate for a non Weierstrass semigroup. In this search certain semigroups L in LLdifficult, where the computation is particular heavy are excluded.

i1 : elapsedTime nonWeierstrassSemigroups(6,7)
(6, 7,  all semigroups are smoothable) -- 1.05147s elapsed


o1 = {}

o1 : List
i2 : LLdifficult={{6, 8, 9, 11}}

o2 = {{6, 8, 9, 11}}

o2 : List
i3 : elapsedTime nonWeierstrassSemigroups(6,8,LLdifficult,Verbose=>true)
(17, 5)
{6, 7, 8, 17}
unfolding
 -- .330266s elapsed
flatteningRelations
 -- .128766s elapsed
next gb
 -- .00169769s elapsed
true
 -- .766509s elapsed
{6, 7, 9, 17}
unfolding
 -- .317045s elapsed
flatteningRelations
 -- .14756s elapsed
next gb
 -- .002467s elapsed
decompose
 -- .115153s elapsed
number of components: 2
support c, codim c: {(2, 2), (5, 2)}
{0, -1}
 -- 2.26959s elapsed
{6, 8, 9, 10}
unfolding
 -- .0899693s elapsed
flatteningRelations
 -- .0994204s elapsed
next gb
 -- .000348012s elapsed
true
 -- .565285s elapsed
{6, 8, 10, 11, 13}
unfolding
 -- .423299s elapsed
flatteningRelations
 -- .184795s elapsed
next gb
 -- .00374185s elapsed
decompose
 -- .879614s elapsed
number of components: 1
support c, codim c: {(5, 1)}
{-1}
 -- 2.36371s elapsed
 -- 5.96523s elapsed
0

 -- .00000292s elapsed
 -- 5.99641s elapsed
{}

o3 = {{6, 8, 9, 11}}

o3 : List

In the verbose mode we get timings of various computation steps and further information. The first line, (17,5), indicates that there 17 semigroups of multiplicity 6 and genus 8 of which only 5 is not flagged as smoothable by the function knownExample. The second line, {6, 7, 8, 17}, gives the current semigroup. The timing under various headers tells how much time was used in each of the steps.

See also

Ways to use nonWeierstrassSemigroups:

For the programmer

The object nonWeierstrassSemigroups is a method function with options.