42 research outputs found
Donaldson-Thomas invariants, torus knots, and lattice paths
In this paper we find and explore the correspondence between quivers, torus
knots, and combinatorics of counting paths. Our first result pertains to quiver
representation theory -- we find explicit formulae for classical generating
functions and Donaldson-Thomas invariants of an arbitrary symmetric quiver. We
then focus on quivers corresponding to torus knots and show that their
classical generating functions, in the extremal limit and framing , are
generating functions of lattice paths under the line of the slope .
Generating functions of such paths satisfy extremal A-polynomial equations,
which immediately follows after representing them in terms of the Duchon
grammar. Moreover, these extremal A-polynomial equations encode
Donaldson-Thomas invariants, which provides an interesting example of
algebraicity of generating functions of these invariants. We also find a
quantum generalization of these statements, i.e. a relation between motivic
quiver generating functions, quantum extremal knot invariants, and -weighted
path counting. Finally, in the case of the unknot, we generalize this
correspondence to the full HOMFLY-PT invariants and counting of Schr\"oder
paths.Comment: 45 pages. Corrected typos in new versio
The change of feedback invariants under one row perturbation
AbstractIn this paper we completely characterize possible feedback invariants of a rectangular matrix under small additive perturbations on one of its rows
Parasupersymmetric Quantum Mechanics of Order 3 and a Generalized Witten Index
In this paper we generalize the Rubakov-Spiridonov parasupersymmetry algebra
to the order 3 case. We also generalize the notion of the Witten index, and we
provide a class of models satisfying our parasupersymmetry algebra. Finally, we
show that there is a correspondence between the Hamiltonian and the index in
our class of models
Homological thickness and stability of torus knots
In this paper we show that the non-alternating torus knots are homologically
thick, i.e. that their Khovanov homology occupies at least three diagonals.
Furthermore, we show that we can reduce the number of full twists of the torus
knot without changing certain part of its homology, and consequently, we show
that there exists stable homology of torus knots conjectured by Dunfield, Gukov
and Rasmussen in \cite{dgr}. Since our main tool is the long exact sequence in
homology, we have applied our approach in the case of the Khovanov-Rozansky
() homology, and thus obtained analogous stability properties of
homology of torus knots, also conjectured in \cite{dgr}.Comment: 24 pages, expanded Section
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Quadruply-graded colored homology of knots
We conjecture the existence of four independent gradings in colored HOMFLYPT homology, and make qualitative predictions of various interesting structures and symmetries in the colored homology of arbitrary knots. We propose an explicit conjectural description for the rectangular colored homology of torus knots, and identify the new gradings in this context. While some of these structures have a natural interpretation in the physical realization of knot homologies based on counting supersymmetric configurations (BPS states, instantons, and vortices), others are completely new. They suggest new geometric and physical realizations of colored HOMFLYPT homology as the Hochschild homology of the category of branes in a LandauāGinzburg B-model or, equivalently, in the mirror A-model. Supergroups and supermanifolds are surprisingly ubiquitous in all aspects of this work
Postkrizni pravci kretanja zaposlenosti u Srbiji
Svetska ekonomska kriza iz 2008. godine ima negativne posledice po privredna kretanja u Srbiji. Zbog smanjene tražnje, kako na domaÄim, tako i na stranim tržiÅ”tima, dolazi isprva do drastiÄnog pada potroÅ”nje i trgovine sa inostranstvom. Usporena privredna aktivnost, smanjena tražnja, pesimistiÄka oÄekivanja, inflatorni pritisak, nestabilna i nagla deprecijacija domaÄe valute, smanjen nivo priliva stranih direktnih investicija, kao i poveÄanje javnog duga, obeležili su period izmeÄu 2008. i 2010. godine. Kroz mehanizam smanjenih investicija, umanjenu inostranu tražnju za domaÄim proizvodima, kao i kroz složeniji pristup finansijskim sredstvima, svetska ekonomska kriza se preliva u Srbiju. DomaÄe posledice: manji budžetski prihodi, poveÄani socijalni izdaci, snažna deprecijacija u odnosu na evro, nejedinstvena politika fiskalnih i monetarnih vlasti, Å”to ŃŠµ sve imalo uticaja na veoma strmi pad zaposlenosti i standarda. U ovom radu se osvrÄemo na uzroke krize u Srbiji, koja nije u potpunosti uvezena iz inostranstva, veÄ poseduje i odlike uzrokovane unutar srpske privede. Potom, daÄemo sektorski prikaz dinamike zaposlenosti u periodu posle 2000. godine, sa analizom stanja u onim sektorima koji su kljuÄni za zaposlenost
BPS states, knots and quivers
We argue how to identify the supersymmetric quiver quantum mechanics description of BPS states, which arise in string theory in brane systems representing knots. This leads to a surprising relation between knots and quivers: to a given knot, we associate a quiver, so that various types of knot invariants are expressed in terms of characteristics of a moduli space of representations of the corresponding quiver. This statement can be regarded as a novel type of categorification of knot invariants, and among its various consequences we find that Labastida-MariƱo-Ooguri-Vafa (LMOV) invariants of a knot can be expressed in terms of motivic Donaldson-Thomas invariants of the corresponding quiver; this proves integrality of LMOV invariants (once the corresponding quiver is identified), conjectured originally based on string theory and M-theory arguments
Knots-quivers correspondence
We introduce and explore the relation between knot invariants and quiver representation theory, which follows from the identification of quiver quantum mechanics in Dābrane systems representing knots. We identify various structural properties of quivers associated to knots, and identify such quivers explicitly in many examples, including some infinite families of knots, all knots up to 6 crossings, and some knots with thick homology. Moreover, based on these properties, we derive previously unknown expressions for colored HOMFLYāPT polynomials and superpolynomials for various knots. For all knots, for which we identify the corresponding quivers, the LMOV conjecture for all symmetric representations (i.e. integrality of relevant BPS numbers) is automatically proved