Lax Familial Representability and Lax Generic Factorizations

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F20%3A00117741" target="_blank" >RIV/00216224:14310/20:00117741 - isvavai.cz</a>

Výsledek na webu

<a href="http://www.tac.mta.ca/tac/volumes/35/37/35-37.pdf" target="_blank" >http://www.tac.mta.ca/tac/volumes/35/37/35-37.pdf</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Lax Familial Representability and Lax Generic Factorizations

Popis výsledku v původním jazyce

A classical result due to Diers shows that a copresheaf F: A -&gt; Set on a category A is a coproduct of representables precisely when each connected component of F's category of elements has an initial object. Most often, this condition is imposed on a copresheaf of the form B (X, T-) for a functor T : A -&gt; B, in which case this property says that T admits generic factorizations at X, or equivalently that T is familial at X. A classical result due to Diers shows that a copresheaf F: A -&gt; Set on a category A is a coproduct of representables precisely when each connected component of F's category of elements has an initial object. Most often, this condition is imposed on a copresheaf of the form B (X, T-) for a functor T : A -&gt; B, in which case this property says that T admits generic factorizations at X, or equivalently that T is familial at X. Here we generalize these results to the two-dimensional setting, replacing A with an arbitrary bicategory A, and Set with Cat. In this two-dimensional setting, simply asking that a pseudofunctor F: A -&gt; Cat be a coproduct of representables is often too strong of a condition. Instead, we will only ask that F be a lax conical colimit of representables. This in turn allows for the weaker notion of lax generic factorizations (and lax familial representability) for pseudofunctors of bicategories T : A -&gt; B. We also compare our lax familial pseudofunctors to Weber's familial 2-functors, finding our description is more general (not requiring a terminal object in A), though essentially equivalent when a terminal object does exist. Moreover, our description of lax generics allows for an equivalence between lax generic factorizations and lax familial representability. Finally, we characterize our lax familial pseudofunctors as right lax F-adjoints followed by locally discrete fibrations of bicategories, which in turn yields a simple definition of parametric right adjoint pseudofunctors. We also compare our lax familial pseudofunctors to Weber's familial 2-functors, finding our description is more general (not requiring a terminal object in A), though essentially equivalent when a terminal object does exist. Moreover, our description of lax generics allows for an equivalence between lax generic factorizations and lax familial representability. Finally, we characterize our lax familial pseudofunctors as right lax F-adjoints followed by locally discrete fibrations of bicategories, which in turn yields a simple definition of parametric right adjoint pseudofunctors.

Název v anglickém jazyce

Lax Familial Representability and Lax Generic Factorizations

Popis výsledku anglicky

A classical result due to Diers shows that a copresheaf F: A -&gt; Set on a category A is a coproduct of representables precisely when each connected component of F's category of elements has an initial object. Most often, this condition is imposed on a copresheaf of the form B (X, T-) for a functor T : A -&gt; B, in which case this property says that T admits generic factorizations at X, or equivalently that T is familial at X. A classical result due to Diers shows that a copresheaf F: A -&gt; Set on a category A is a coproduct of representables precisely when each connected component of F's category of elements has an initial object. Most often, this condition is imposed on a copresheaf of the form B (X, T-) for a functor T : A -&gt; B, in which case this property says that T admits generic factorizations at X, or equivalently that T is familial at X. Here we generalize these results to the two-dimensional setting, replacing A with an arbitrary bicategory A, and Set with Cat. In this two-dimensional setting, simply asking that a pseudofunctor F: A -&gt; Cat be a coproduct of representables is often too strong of a condition. Instead, we will only ask that F be a lax conical colimit of representables. This in turn allows for the weaker notion of lax generic factorizations (and lax familial representability) for pseudofunctors of bicategories T : A -&gt; B. We also compare our lax familial pseudofunctors to Weber's familial 2-functors, finding our description is more general (not requiring a terminal object in A), though essentially equivalent when a terminal object does exist. Moreover, our description of lax generics allows for an equivalence between lax generic factorizations and lax familial representability. Finally, we characterize our lax familial pseudofunctors as right lax F-adjoints followed by locally discrete fibrations of bicategories, which in turn yields a simple definition of parametric right adjoint pseudofunctors. We also compare our lax familial pseudofunctors to Weber's familial 2-functors, finding our description is more general (not requiring a terminal object in A), though essentially equivalent when a terminal object does exist. Moreover, our description of lax generics allows for an equivalence between lax generic factorizations and lax familial representability. Finally, we characterize our lax familial pseudofunctors as right lax F-adjoints followed by locally discrete fibrations of bicategories, which in turn yields a simple definition of parametric right adjoint pseudofunctors.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

10101 - Pure mathematics

Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Theory and Applications of Categories

ISSN

1201-561X

e-ISSN

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Svazek periodika

35

Číslo periodika v rámci svazku

37

Stát vydavatele periodika

CA - Kanada

Počet stran výsledku

52

Strana od-do

1424-1475

Kód UT WoS článku

000594117700037

EID výsledku v databázi Scopus

2-s2.0-85089849293