complex(FilteredComplex) -- the ambient chain complex of a filtered complex

i1 : A = QQ[x,y];

i2 : C = koszulComplex vars A

      1      2      1
o2 = A  <-- A  <-- A
                    
     0      1      2

o2 : Complex

i3 : K = filteredComplex C;

i4 : complex K

      1      2      1
o4 = A  <-- A  <-- A
                    
     0      1      2

o4 : Complex

i5 : K_infinity

      1      2      1
o5 = A  <-- A  <-- A
                    
     0      1      2

o5 : Complex