Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Homological Algebra on Graded Posets   We describe the projectives in the category of functors from a graded poset
to abelian groups. Based on this description we define a related condition,
pseudo-projectivity, and we prove that this condition is enough for the
vanishing of the derived direct limits. We apply this result to deduce a
generalized version of a theorem of Whitehead for the pushout. The dual results
for inverse limits are also considered.
  We present two methods to compute integral cohomology of posets, a local one
a and a global one. The local method is applicable as soon as the sub-posets
under each object possess certain structure. This is the case for simplicial
complexes, simplex-like posets and for Quillen's complex of a finite group. The
global method is related to Morse Theory.

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The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat