# netPage -- display a small portion of a given Spectral Sequence page

## Synopsis

• Usage:
E' = netPage(E,L1,L2)
• Inputs:
• Outputs:

## Description

Produces the portion of a given spectral sequence page that lies in the square with given bottom right and top left coordinates.

 i1 : R = QQ[x]; i2 : S = R/ideal"x2"; i3 : N = S^1/ideal"x"; i4 : M = R^1/R_0; i5 : C = res M; i6 : C' = C ** S; i7 : D = res(N,LengthLimit => 10); i8 : E0 = C' ** (filteredComplex D); i9 : E = prune spectralSequence E0;

The E_2 page has nonzero E_2^{p,q} when 0 <= p <= 10 and 0 <= q <= 1, so we may ask to restrict the display to 2 <= p <= 6 and 0 <= q <= 1.

netPage(E_2,{2,0},{6,1})

If we ask for a square that is too large, only the relevant portion of the page will be displayed.

 i10 : R = QQ[x]; i11 : S = R/ideal"x2"; i12 : N = S^1/ideal"x"; i13 : M = R^1/R_0; i14 : C = res M; i15 : C' = C ** S; i16 : D = res(N,LengthLimit => 10); i17 : E0 = C' ** (filteredComplex D); i18 : E = prune spectralSequence E0; i19 : netPage(E_2,{-5,0},{7,1}) +------------------+------------------+------------------+------------------+------------------+------------------+------------------+------------------+ o19 = |cokernel {2} | x ||cokernel {3} | x ||cokernel {4} | x ||cokernel {5} | x ||cokernel {6} | x ||cokernel {7} | x ||cokernel {8} | x ||cokernel {9} | x || | | | | | | | | | |{0, 1} |{1, 1} |{2, 1} |{3, 1} |{4, 1} |{5, 1} |{6, 1} |{7, 1} | +------------------+------------------+------------------+------------------+------------------+------------------+------------------+------------------+ |cokernel | x | |cokernel {1} | x ||cokernel {2} | x ||cokernel {3} | x ||cokernel {4} | x ||cokernel {5} | x ||cokernel {6} | x ||cokernel {7} | x || | | | | | | | | | |{0, 0} |{1, 0} |{2, 0} |{3, 0} |{4, 0} |{5, 0} |{6, 0} |{7, 0} | +------------------+------------------+------------------+------------------+------------------+------------------+------------------+------------------+

## Ways to use netPage :

• "netPage(Page,List,List)"

## For the programmer

The object netPage is .