55XX 


Algebraic topology 

55Uxx 

Applied homological algebra and category theory [See also 18Gxx] 


55U05 
Abstract complexes 


55U10 
Simplicial sets and complexes 


55U15 
Chain complexes 


55U20 
Universal coefficient theorems, Bockstein operator 


55U25 
Homology of a product, Künneth formula 


55U30 
Duality 


55U35 
Abstract and axiomatic homotopy theory 


55U40 
Topological categories, foundations of homotopy theory 


55U99 
None of the above, but in this section 