 Atiyah–Hirzebruch spectral sequence

The skeletal filtration of a CW complex gives this spectral sequence, with differential of bidegree $(r,1-r)$ in cohomological grading. For a finite complex the filtration is finite and convergence is bounded. In a multiplicative theory the associated graded product is the ordinary cohomology product with coefficients in the theory's coefficient ring.

The Atiyah–Hirzebruch spectral sequence is an important tool in algebraic topology, specifically in the computation of homotopy groups and cohomology theories. It provides a way to calculate the homology or cohomology of a space using a spectral sequence that is associated with a specific filtration. The original context for the spectral sequence primarily relates to complex vector bundles and characteristic classes.