Spectral sequence
= Spectral sequence
{title2=$(E_r^{p,q},d_r)$}
{wiki}
A succession of bigraded pages with $E_{r+1}=H(E_r,d_r)$. In the cohomological convention, the differential has bidegree $(r,1-r)$. A filtered complex produces such successive approximations to its <cohomology>.