nonWeierstrassSemigroups -- Find possibly non Weierstrass Semigroups

Usage:

LL=nonWeierstrassSemgroups(m,g)

LL=nonWeierstrassSemgroups(m,g,LLdifficult)
Inputs:
- m, an integer, the multiplicity of a semigroup
- g, an integer, the genus of a semigroup
- LLdifficult, a list, List of difficult semigroups which we exclude from the test
Optional inputs:
- BaseField
- Verbose => ..., default value false
Outputs:
- LL, a list, List of possible non Weierstrass semigroups including LLdifficult

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) -- 1.30778s 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
 -- .41433s elapsed
flatteningRelations
 -- .154531s elapsed
next gb
 -- .00184889s elapsed
true
 -- .880447s elapsed
{6, 7, 9, 17}
unfolding
 -- .372134s elapsed
flatteningRelations
 -- .208932s elapsed
next gb
 -- .00230825s elapsed
decompose
 -- .120448s elapsed
number of components: 2
support c, codim c: {(2, 2), (5, 2)}
{0, -1}
 -- 2.73139s elapsed
{6, 8, 9, 10}
unfolding
 -- .121857s elapsed
flatteningRelations
 -- .112506s elapsed
next gb
 -- .000362805s elapsed
true
 -- .607447s elapsed
{6, 8, 10, 11, 13}
unfolding
 -- .50432s elapsed
flatteningRelations
 -- .181776s elapsed
next gb
 -- .00352542s elapsed
decompose
 -- .788781s elapsed
number of components: 1
support c, codim c: {(5, 1)}
{-1}
 -- 2.4541s elapsed
 -- 6.67349s elapsed
0

 -- .000002881s elapsed
 -- 6.74781s 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.

Ways to use nonWeierstrassSemigroups:

nonWeierstrassSemigroups(ZZ,ZZ)
nonWeierstrassSemigroups(ZZ,ZZ,List)

For the programmer

The object nonWeierstrassSemigroups is a method function with options.

The source of this document is in /build/macaulay2-DehBdI/macaulay2-1.25.06+ds/M2/Macaulay2/packages/NumericalSemigroups.m2:2605:0.

nonWeierstrassSemigroups -- Find possibly non Weierstrass Semigroups

Description

See also

Ways to use nonWeierstrassSemigroups:

For the programmer