foldComplex -- converts a chain complex into a differential module

Synopsis

• Usage:

  foldComplex(C)

• Inputs:
  • C, a complex,
  • d, an integer,
• Outputs:
  • a differential module,

Description

i1 : R = QQ[x,y];

i2 : C = complex res ideal(x,y)

      1      2      1
o2 = R  <-- R  <-- R
                    
     0      1      2

o2 : Complex

i3 : D = foldComplex(C,0);

i4 : D.dd_1

o4 = {0} | 0 x y 0  |
     {1} | 0 0 0 -y |
     {1} | 0 0 0 x  |
     {2} | 0 0 0 0  |

             4      4
o4 : Matrix R  <-- R

See also

• differentialModule(Complex) -- converts a complex into a differential module
• unfold -- converts a differential module into a 1-periodic complex
• resDM -- uses a "killing cycles"-style construction to find a free resolution of a differential module
• resMinFlag -- gives a minimal free flag resolution of a differential module of degree 0