activity
20022023
most citedGroupoids in combinatorics -- applications of a theory of local symmetries

6 citations · 34 across the 28 of their papers we have counts for

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25 papers · 1 filter

math.CO2023★ 1 cited

Polytopality of simple games

Marinko Timotijević, Rade T. Živaljević, Filip D. Jevtić

The Bier sphere and the canonical fan are combinatorial/geometric companions of a simple game …

math.CO2022

Colored Tverberg Theorems for non-prime powers

Leandro V. Mauri, Rade T. Živaljević, Denise de Mattos +1

We prove a relative of the Optimal (Type B)} Colored Tverberg theorem of Živaljević and Vrećica which modifies this results in two different ways. (1) Our result is valid if the nu…

math.CO2022

Envy-free division in the presence of a dragon

Gaiane Panina, Rade Živaljević

We prove several results addressing the envy-free division problem in the presence of an unpredictable (secretive) player, called the "dragon". There are two basic scenarios. 1. Th…

math.CO2021

Envy-free division via configuration spaces

Gaiane Panina, Rade Živaljević

The classical approach to envy-free division and equilibrium problems relies on Knaster-Kuratowski-Mazurkiewicz theorem, Sperner's lemma or some extension involving mapping degree.…

math.CO2019

Splitting necklaces, with constraints

Duško Jojić, Gaiane Panina, Rade Živaljević

We prove several versions of N. Alon's "necklace-splitting theorem", subject to additional constraints, as illustrated by the following results. (1) The "almost equicardinal neckla…

math.CO2018

A Tverberg type theorem for collectively unavoidable complexes

Duško Jojić, Gaiane Panina, Rade Živaljević

We prove (Theorem 2.4) that the symmetrized deleted join of a "balanced family" of collectively -unavoidabl…

math.CO2017

Cyclohedron and Kantorovich-Rubinstein polytopes

Filip D. Jevtić, Marija Jelić, Rade T. Živaljević

We show that the cyclohedron (Bott-Taubes polytope) arises as the dual of a Kantorovich-Rubinstein polytope , where is a quasi-metric (asymmetric distance function…

math.CO2015

Symmetric multiple chessboard complexes and a new theorem of Tverberg type

Duško Jojić, Siniša Vrećica, Rade Živaljević

We prove a new theorem of Tverberg type which confirms the conjecture of Blagojevic, Frick, and Ziegler about the existence of "balanced Tverberg partitions" (Conjecture 6.6 in, Tv…

math.CO2014

Multiple chessboard complexes and the colored Tverberg problem

Duško Jojić, Siniša T. Vrećica, Rade T. Živaljević

Following D.B. Karaguezian, V. Reiner, and M.L. Wachs (Matching Complexes, Bounded Degree Graph Complexes, and Weight Spaces of -Complexes, Journal of Algebra 2001) we study th…

math.CO2014★ 1 cited

Symmetric polyomino tilings, tribones, ideals, and Groebner bases

Manuela Muzika Dizdarevic, Rade T. Zivaljevic

We apply the theory of Groebner bases to the study of signed, symmetric polyomino tilings of planar domains. Complementing the results of Conway and Lagarias we show that the trian…

math.CO2013★ 2 cited

Measurable patterns, necklaces, and sets indiscernible by measure

Sinisa Vrecica, Rade Zivaljevic

In some recent papers the classical `splitting necklace theorem' is linked in an interesting way with a geometric `pattern avoidance problem'. We explore the topological constraint…

math.CO2009★ 4 cited

Chessboard complexes indomitable

S. T. Vrecica, R. T. Zivaljevic

We give an alternative proof of the striking new Tverberg type theorem of Blagojevic and Ziegler, arXiv:0910.4987v1 [math.CO]. Our method also yields some new cases of "constrained…

math.CO2008★ 1 cited

Fulton-MacPherson compactification, cyclohedra, and the polygonal pegs problem

Sinisa Vrecica, Rade Zivaljevic

The cyclohedron (Bott-Taubes polytope) arises both as the polyhedral realization of the poset of all cyclic bracketings of a circular word and as an essential part of the Fulton-Ma…

math.CO2007

Oriented matroids and Ky Fan's theorem

Rade T. Zivaljevic

L. Lovasz has shown that Sperner's combinatorial lemma admits a generalization involving a matroid defined on the set of vertices of the associated triangulation. Inspired by this…

math.CO2006

Splitting multidimensional necklaces

Mark de Longueville, Rade Zivaljevic

The well-known "splitting necklace theorem" of Noga Alon says that each "necklace" having beads of n different colors can be fairly divided between k "thieves" by at most n(k-1) cu…

math.CO2006★ 6 cited

Groupoids in combinatorics -- applications of a theory of local symmetries

Rade T. Zivaljevic

An objective of the theory of combinatorial groupoids is to introduce concepts like "holonomy", "parallel transport", "bundles", "combinatorial curvature" etc. in the context of si…

math.CO2005★ 2 cited

Combinatorial groupoids, cubical complexes, and the Lovasz conjecture

Rade T. Zivaljevic

A foundation is laid for a theory of combinatorial groupoids, allowing us to use concepts like ``holonomy'', ``parallel transport'', ``bundles'', ``combinatorial curvature'' etc. i…

math.CO2005

The Borsuk-Ulam-property, Tucker-property and constructive proofs in combinatorics

Mark de Longueville, Rade T. Zivaljevic

This article is concerned with a general scheme on how to obtain constructive proofs for combinatorial theorems that have topological proofs so far. To this end the combinatorial c…

math.CO2005

Parallel transport of -complexes and the Lovasz conjecture

Rade T. Zivaljevic

The groupoid of projectivities, introduced by M. Joswig, serves as a basis for a construction of parallel transport of graph and more general -complexes. In this framework we…

math.CO2004★ 1 cited

Equipartitions of measures in

Rade T. Zivaljevic

We prove that each measure in admits an equipartition by 4 hyperplanes, provided that it is symmetric with respect to a 2-dimensional, affine subspace of . Moreo…

math.CO2004★ 3 cited

WI-posets, graph complexes and Z_2-equivalences

Rade T. Zivaljevic

We introduce WI-posets as intermediate objects in the study of Z_2-homotopy types of graph complexes. It turns out that (almost) all graph complexes associated to a graph can be vi…

math.CO2003

Topology and Combinatorics of Partitions of Masses by Hyperplanes

Peter Mani-Levitska, Sinisa Vrecica, Rade Zivaljevic

One of our result is that 5 measurable sets in always admit an equipartition by 2 hyperplanes. This is an instance of a general equipartition problem (formulated by B. Gr{\"…

math.CO2003

Symmetric products of surfaces and the cycle index

Pavle Blagojevic, Vladimir Grujic, Rade Zivaljevic

We express the signature of the symmetric product of an (open) surface in terms of the cycle index of , a polynomial which or…

math.CO2003

Arrangements of symmetric products of spaces

Pavle Blagojevic, Vladimir Grujic, Rade Zivaljevic

Using the topological technique of diagrams of spaces, we calculate the homology of the union and the complement of finite arrangements of subspaces of the form i…