#
Higher cospans and weak cubical categories (Cospans in algebraic topology, I)

##
Marco Grandis

We define a notion of * weak cubical category*, abstracted from the
structure of n-cubical cospans $x : \wedge^n \to X$ in a category $X$
where $\wedge$ is the `formal cospan' category. These diagrams form a
cubical set with compositions $x +_i y$ in all directions, which are
computed using pushouts and behave `categorically' in a weak sense, up to
suitable comparisons. Actually, we work with a `symmetric cubical
structure', which includes the transposition symmetries, because this
allows for a strong simplification of the coherence conditions. These
notions will be used in subsequent papers to study topological cospans and
their use in Algebraic Topology, from tangles to cobordisms of manifolds.

We also introduce the more general notion of a *multiple category*,
where - to start with - arrows belong to different sorts, varying in a
countable family, and symmetries must be dropped. The present examples
seem to show that the symmetric cubical case is better suited for
topological applications.

Keywords:
weak cubical category, multiple category, double category,
cubical sets, spans, cospans

2000 MSC:
18D05, 55U10

Revised 2007-07-27. Original version at
http://www.tac.mta.ca/tac/volumes/18/12/18-12a.dvi

*Theory and Applications of Categories,*
Vol. 18, 2007,
No. 12, pp 321-347.

http://www.tac.mta.ca/tac/volumes/18/12/18-12.dvi

http://www.tac.mta.ca/tac/volumes/18/12/18-12.ps

http://www.tac.mta.ca/tac/volumes/18/12/18-12.pdf

ftp://ftp.tac.mta.ca/pub/tac/html/volumes/18/12/18-12.dvi

ftp://ftp.tac.mta.ca/pub/tac/html/volumes/18/12/18-12.ps

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