# makeRes -- creates a resolution starting from three matrices

## Synopsis

• Usage:
makeRes(d1,d2,d3)
• Inputs:
• d1, , of the differential in degree 1
• d2, , of the differential in degree 2
• d3, , of the differential in degree 3
• Outputs:
• , the resolution with differentials d1, d2, d3.

## Description

Creates a resolution of length 3 that has the given three matrices as differentials.

 i1 : Q = QQ[x,y,z]; i2 : d1=matrix{{-x^2,z^2-x*y,-y^2,-x*z,-y*z}} o2 = | -x2 -xy+z2 -y2 -xz -yz | 1 5 o2 : Matrix Q <--- Q i3 : d2=matrix{{0,0,z,0,-y},{0,0,0,-y,x},{-z,0,0,x,0},{0,y,-x,0,z},{y,-x,0,-z,0}} o3 = | 0 0 z 0 -y | | 0 0 0 -y x | | -z 0 0 x 0 | | 0 y -x 0 z | | y -x 0 -z 0 | 5 5 o3 : Matrix Q <--- Q i4 : d3=transpose d1 o4 = {-2} | -x2 | {-2} | -xy+z2 | {-2} | -y2 | {-2} | -xz | {-2} | -yz | 5 1 o4 : Matrix Q <--- Q i5 : makeRes(d1,d2,d3) 1 5 5 1 o5 = Q <-- Q <-- Q <-- Q <-- 0 0 1 2 3 4 o5 : ChainComplex

## For the programmer

The object makeRes is .