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)
 -- 1.56085s 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
 -- .436854s elapsed
flatteningRelations
 -- .176241s elapsed
next gb
 -- .001953s elapsed
true
 -- .976831s elapsed
{6, 7, 9, 17}
unfolding
 -- .446681s elapsed
flatteningRelations
 -- .171884s elapsed
next gb
 -- .00279172s elapsed
decompose
 -- .175688s elapsed
number of components: 2
support c, codim c: {(2, 2), (5, 2)}
{0, -1}
 -- 3.20249s elapsed
{6, 8, 9, 10}
unfolding
 -- .105417s elapsed
flatteningRelations
 -- .180868s elapsed
next gb
 -- .000491059s elapsed
true
 -- .838535s elapsed
{6, 8, 10, 11, 13}
unfolding
 -- .538934s elapsed
flatteningRelations
 -- .250105s elapsed
next gb
 -- .00454054s elapsed
decompose
 -- 1.00089s elapsed
number of components: 1
support c, codim c: {(5, 1)}
{-1}
 -- 2.84332s elapsed
 -- 7.86131s elapsed
0

{}
 -- .000004509s elapsed
 -- 7.95628s 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 NumericalSemigroups.m2:2605:0.

nonWeierstrassSemigroups -- Find possibly non Weierstrass Semigroups

Description

See also

Ways to use nonWeierstrassSemigroups:

For the programmer