directed object' (Rev #3, changes)

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Definition (interval object)

Let CC be a closed monoidal (V-enriched for some VV) homotopical category, let ** denote the tensor unit of CC. Then the cospan category (same objects and cospans as morphisms) is VV-enriched, too.

An interval object is defined to be a cospan *aIb**\stackrel{a}{\rightarrow}I\stackrel{b}{\leftarrow}*.

The pushout I 2I^{\coprod_2} of this diagram satisfies *[I,I 2] *{}_*[ I,I^{\coprod_2}]_*\simeq is contractible (see co-span for this notation).

Definition (directed object)

Let C V C V be a closed monoidal (V-enriched category, for let some V C V C ) homotopical be category, let*V * V -enriched, denote closed the monoidal tensor homotopical unit category, of letC* C * which denote we assume to be the terminal tensor object, unit let of I C I C denote which we assume to be the interval terminal object object, of let C I C I , let denote the interval object of X C X C , be let a pointed object of C X C X . Let be a pointed object of D C D C . be Let the functorD:CV D:C\to D V be the functor D:CVD:C\to V, X\mapsto [I,X]$.

A direction in CC is defined to be a subfunctor of DD. In this case dXd X is called a direction for XX. A global element of dXdX is called a dd-directed path in XX.

The collection of dd-directed path in XX satisfies the following properties:

A direction for XX is defined to be a subobject dXdX of [I,X][I,X] whose collection ddp(X)ddp(X) of global elements, called directed paths (or more precisely d*directedpathsof d*-directed d paths of X$), -directed satisfies paths ofXX), satisfies

(1) The DD image of every map I*XI\to *\to X factoring over the point is in ddp(X)ddp(X).

(2) The collection of global elements of d ddp(X) d ddp(X) X is closed under pushout. the tensor product. Forα,βddp(X) \alpha \alpha,\beta\in ddp(X) , their pushoutαβ \alpha\otimes \beta global elements of dXd X, their pushout αβ\alpha\otimes \beta is called their composition.

A directed object is defined to be a pair dX:=(X,dX){}_d X:=(X,dX) consisting of an object XX of CC and a direction dXdX for XX.

A morphism of directed objects f:(X,dX)(Y,dy)f:(X,dX)\to (Y,dy) is defined to be a pair (f,df)(f,df) making

X f Y d d dX df dY\array{ X& \stackrel{f}{\to}& Y \\ \downarrow^d&&\downarrow^d \\ dX& \stackrel{df}{\to}& d Y }

Let CC be VV-enriched, closed monoidal homotopical category, let II denote the tensor unit of CC.


A directed-path-space objects is defined.

Revision on November 5, 2012 at 19:44:06 by Stephan Alexander Spahn?. See the history of this page for a list of all contributions to it.