Macaulay2 » Documentation
Packages » NumericalSemigroups :: buchweitzCriterion
next | previous | forward | backward | up | index | toc

buchweitzCriterion -- Does L satisfies the Buchweitz criterion?

Synopsis

Description

A Weierstrass semigroups L satisfies

3*(genus L-1) -#sums(G,G) >=0.

The function returns this difference.

i1 : L={7,12,13}

o1 = {7, 12, 13}

o1 : List
i2 : buchweitzCriterion L

o2 = 0
i3 : L= buchweitz 0

o3 = {13, 14, 15, 16, 17, 18, 20, 22, 23}

o3 : List
i4 : buchweitzCriterion L

o4 = -1
i5 : (H,M)=allSemigroups L

o5 = (| 13 13 13 13 13 26 13 26  13  13  26  26  |, | 14 15 16 17 18 32 20
      | 13 26 39 52 65 78 91 104 117 130 143 156 |  | 14 28 42 56 70 84 98
     ------------------------------------------------------------------------
     34  22  23  37  38  |)
     112 126 140 154 168 |

o5 : Sequence
i6 : b=(entries M)_0

o6 = {14, 15, 16, 17, 18, 32, 20, 34, 22, 23, 37, 38}

o6 : List
i7 : g=(entries H)_0

o7 = {13, 13, 13, 13, 13, 26, 13, 26, 13, 13, 26, 26}

o7 : List
i8 : apply(3,i->buchweitzCriterion(13,b+i*g))

o8 = {-1, -2, -3}

o8 : List

See also

Ways to use buchweitzCriterion:

For the programmer

The object buchweitzCriterion is a method function.