Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Straight homotopy invariants   Let $X$ and $Y$ be spaces and $M$ be an abelian group. A homotopy invariant
$f\colon [X,Y]\to M$ is called straight if there exists a homomorphism $F\colon
L(X,Y)\to M$ such that $f([a])=F(\langle a\rangle)$ for all $a\in C(X,Y)$. Here
$\langle a\rangle\colon\langle X\rangle\to\langle Y\rangle$ is the homomorphism
induced by $a$ between the abelian groups freely generated by $X$ and $Y$ and
$L(X,Y)$ is a certain group of `admissible' homomorphisms. We show that all
straight invariants can be expressed through a `universal' straight invariant
of homological nature.

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The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: physics
7
The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: econ