8,447 research outputs found
Distributive laws, pseudodistributive laws and decagons
We give alternative definitions of distributive laws and pseudodistributive
laws involving the decagonal coherence conditions which naturally arise when
the involved monads and pseudomonads are presented in extensive form. We then
use these results to give a number of simplifications in the coherence
conditions for distributive laws and pseudodistributive laws. In particular, we
show that five coherence axioms suffice in the usual definition of
pseudodistributive laws, we give simple descriptions of distributive laws and
pseudodistributive laws in terms of (pseudo)algebra structure maps, and we give
concise definitions of distributive laws and pseudodistributive laws in
no-iteration form.Comment: 27 pages; added the definition of a pseudodistributive law in
no-iteration for
On the formal theory of pseudomonads and pseudodistributive laws
We contribute to the formal theory of pseudomonads, i.e. the analogue for
pseudomonads of the formal theory of monads. In particular, we solve a problem
posed by Steve Lack by proving that, for every Gray-category K, there is a
Gray-category Psm(K) of pseudomonads, pseudomonad morphisms, pseudomonad
transformations and pseudomonad modifications in K. We then establish a
triequivalence between Psm(K) and the Gray-category of pseudomonads introduced
by Marmolejo. Finally, these results are applied to give a clear account of the
coherence conditions for pseudodistributive laws. 40 pages. Comments welcome.Comment: This submission replaces arXiv:0907:1359v1, titled "On the coherence
conditions for pseudo-distributive laws". 40 page
Polycategories via pseudo-distributive laws
AbstractIn this paper, we give a novel abstract description of Szabo's polycategories. We use the theory of double clubs – a generalisation of Kelly's theory of clubs to ‘pseudo’ (or ‘weak’) double categories – to construct a pseudo-distributive law of the free symmetric strict monoidal category pseudocomonad on Mod over itself qua pseudomonad, and show that monads in the ‘two-sided Kleisli bicategory’ of this pseudo-distributive law are precisely symmetric polycategories
Not every pseudoalgebra is equivalent to a strict one
We describe a finitary 2-monad on a locally finitely presentable 2-category
for which not every pseudoalgebra is equivalent to a strict one. This shows
that having rank is not a sufficient condition on a 2-monad for every
pseudoalgebra to be strictifiable. Our counterexample comes from higher
category theory: the strict algebras are strict 3-categories, and the
pseudoalgebras are a type of semi-strict 3-category lying in between
Gray-categories and tricategories. Thus, the result follows from the fact that
not every Gray-category is equivalent to a strict 3-category, connecting
2-categorical and higher-categorical coherence theory. In particular, any
nontrivially braided monoidal category gives an example of a pseudoalgebra that
is not equivalent to a strict one.Comment: 17 pages; added more explanation; final version, to appear in Adv.
Mat
Operads within monoidal pseudo algebras
A general notion of operad is given, which includes as instances, the operads
originally conceived to study loop spaces, as well as the higher operads that
arise in the globular approach to higher dimensional algebra. In the framework
of this paper, one can also describe symmetric and braided analogues of higher
operads, likely to be important to the study of weakly symmetric, higher
dimensional monoidal structures
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