Home Online Manual
Top
Back: PPolyQp
Forward: MacdonaldF
FastBack:
FastForward:
Up: goettsche_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.15.5.6 BettiNumsQp

Procedure from library goettsche.lib (see goettsche_lib).

Usage:
BettiNumsQp(r, n); n, r integers

Return:
list of non-negative integers

Purpose:
computes the Betti numbers of the punctual Quot-scheme of rank r on n points on a plane

Note:
an empty list is returned if n<0 or r<=0

Example:
 
LIB "goettsche.lib";
ring r=0, (z), ls;
// get the Betti numbers of the punctual Hilbert scheme (r=1)
// of 3 points on a plane
print( BettiNumsQp(1, 3) );
==> [1]:
==>    1
==> [2]:
==>    0
==> [3]:
==>    1
==> [4]:
==>    0
==> [5]:
==>    1