3.AIM Workshop: Exact crossing numbers |

Dates | 28 Apr 2014 → 02 May 2014 | [ID=564477] |

Location | American Institute of Mathematics, Palo Alto, United States |

Abstract | This workshop, sponsored by AIM and the NSF, will be devoted to tackling several long-standing open problems in the field of crossing numbers of graphs. |

Weblink | http://www.aimath.org/ARCC/workshops/exactcrossing.html |

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4.Eigenvectors in Graph Theory and Related Problems in Numerical Linear Algebra |

Dates | 05 May 2014 → 09 May 2014 | [ID=579425] |

Location | Providence, United States |

Abstract | The analysis of problems modeled by large graphs is greatly hampered by a lack of efficient computational tools. The purpose of the workshop is to explore possibilities for designing appropriate computational methods that draw on recent advances in numerical methods and scientific computation. Specifically, the questions of how to form the matrices representing graph Laplacians, and how to compute the leading eigenvectors of such matrices will be addressed. It seems likely that these problems will be amenable to algorithms based on randomized projections that dramatically reduce the effective dimensionality of the underlying problems. Such techniques has recently proven highly effective for the related problems of how to find approximate lists of nearest neighbors for clouds of points in high dimensional spaces, and for constructing approximate low-rank factorizations of large matrices. In both cases, a key observation is that the problem of distortions of distances that is inherent to randomized projection techniques can be overcome by using the randomized projections only as pre-conditioners; they inform the algorithm of where to look, and then highly accurate deterministic techniques are used to compute the actual output. The resulting algorithms scale extra-ordinarily well on modern parallel and multicore architectures. To successfully address the enormous problems arising in the analysis of graphs, it is expected that additional machinery will be needed, such as the use of multi-resolution data structures, and more efficient scalable randomized projections. |

Weblink | https://icerm.brown.edu/sp-s14-w4 |

Related subject(s) | Algebra; Applied Maths: Numerical Analysis, Algebra and Computational Mathematics |

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5.Finding Algebraic Structures in Extremal Combinatorial Configurations |

Dates | 19 May 2014 → 23 May 2014 | [ID=564548] |

Location | Institute for Pure and Applied Mathematics (IPAM),, United States |

Abstract | Understanding the fine structure of extremal configurations is a key step in the solution of many problems in extremal combinatorics. For example, in many cases a group action underlies the structure found in an extremal scenario, making the problem amenable to algebraic methods. This principle is illustrated by recent work which has applied techniques from algebra, algebraic geometry, model theory and additive combinatorics to obtain important new results in discrete geometry. We expect this fusion of algebraic geometry and combinatorics to become a very active area of research in the coming months and years. It is our aim to showcase the most exciting results, techniques and recent trends in this workshop. This workshop will include a poster session; a request for posters will be sent to registered participants in advance of the workshop. An application and registration form are available online. |

Weblink | http://www.ipam.ucla.edu/programs/ccgws4/ |

Related subject(s) | Algebra |

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6.FPSAC — 26th International Conference on Formal Power Series and Algebraic Combinatorics |

Dates | 29 Jun 2014 → 03 Jul 2014 | [ID=488365] |

Location | Chicago, IL, United States |

Topics | Topics include all aspects of combinatorics and their relations with other parts of mathematics, physics, computer science, and biology. |

Weblink | https://sites.google.com/site/fpsac2014/ |

Contact | Bridget Tenner; Email: fpsac2014@gmail.com |

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7.Integrability and Cluster Algebras: Geometry and Combinatorics |

Dates | 25 Aug 2014 → 29 Aug 2014 | [ID=575495] |

Location | Providence, United States |

Abstract | This workshop focuses on certain kinds of discrete dynamical systems that are integrable and have interpretations in terms of cluster algebras. Some such systems, like the pentagram map and the octahedral recurrence, are motivated by concrete algebraic constructions (taking determinants) or geometric constructions based on specific configurations of points and lines in the projective plane. The systems of interest in this workshop have connections to Poisson and symplectic geometry, classical integrable PDE such as the KdV and Boussinesq equations and also to cluster algebras. The aim of the workshop is to explore geometric, algebraic, and computational facets of these systems, with a view towards uncovering new phenomena and unifying the work to date. |

Weblink | http://icerm.brown.edu/tw14-4-ica |

Related subject(s) | Geometry and Topology; Algebra |

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8.IWOCA 2014 — International Workshop on Combinatorial Algorithms |

Dates | 15 Oct 2014 → 17 Oct 2014 | [ID=621983] |

Location | Duluth, Minnesota, United States |

Abstract | IWOCA 2014 continues the long and well-established tradition of encouraging high-quality research in theoretical computer science and bringing together specialists and young researchers working in the area. The scientific program will include invited lectures covering the areas of main interest, accepted contributed talks, posters, and a problems session. |

Topics | Algorithms and Data Structures, Applications (including Bioinformatics, Networking, etc.), Combinatorial Enumeration, Combinatorial Optimization, Complexity Theory (Structural and Computational), Computational Biology, Databases (Security, Compression and Information Retrieval), Decompositions and Combinatorial Designs, Discrete and Computational Geometry (including Graph Drawing), Graph Theory and Combinatorics |

Weblink | http://mcs.uwsuper.edu/iwoca2014/ |

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9.Current topics in three-manifolds |

Dates | 17 Oct 2014 → 19 Oct 2014 | [ID=615923] |

Location | Minneapolis, Minnesota, United States |

Weblink | http://math.umn.edu/yamabe/2014/ |

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10.28th Midwest Conference on Combinatorics and Combinatorial Computing |

Dates | 22 Oct 2014 → 24 Oct 2014 | [ID=610401] |

Location | University of Nevada, Las Vegas, United States |

Abstract | The Midwest Conferences on Combinatorics and Combinatorial Computing (MCCCC) are of small size (50 to 70 participants) and have been growing slowly. Papers cover a spectrum of pure and applied combinatorics, including graph theory, design theory, enumeration, and combinatorial computing. For 28th MCCCC, the invited speakers are: Brian Alspach; Saad El-Zanati; Futaba Fujie-Okamoto; Joseph Gallian; Margaret Readdy; Ian Wanless. Contributed papers (15-20 minutes talks) are very welcomed. |

Weblink | http://www.mcccc.info |

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11.AIM Workshop — Combinatorics and complexity of Kronecker coefficients |

Dates | 03 Nov 2014 → 07 Nov 2014 | [ID=611212] |

Location | Palo Alto, CA, United States |

Organizer | American Institute of Mathematics |

Abstract | This workshop, sponsored by AIM and the NSF, will be devoted to the study of Kronecker coefficients which describe the decomposition of tensor products of irreducible representations of a symmetric group into irreducible representations. We concentrate on their combinatorial interpretation, computational aspects and applications to other fields. |

Weblink | http://aimath.org/workshops/upcoming/ |

Related subject(s) | Algebra; Group Theory |

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12.ANALCO15 — Analytic Algorithmics and Combinatorics |

Start date | 04 Jan 2015 | [ID=597439] |

Location | San Diego, California, United States |

Organizer | Society for Industrial and Applied Mathematics (SIAM) |

Weblink | http://www.siam.org/meetings/analco15/ |

Related subject(s) | Applied Mathematics (in general); Algorithms |

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13.ICERM Semester Program: Phase Transitions and Emergent Properties |

Dates | 02 Feb 2015 → 08 May 2015 | [ID=592131] |

Location | Providence, United States |

Abstract | Emergent phenomena are properties of a system of many components which are only evident or even meaningful for the collection as a whole. A typical example is a system of many molecules, whose bulk properties may change from those of a fluid to those of a solid in response to changes in temperature or pressure. The basic mathematical tool for understanding emergent phenomena is the variational principle, most often employed via entropy maximization. The difficulty of analyzing emergent phenomena, however, makes empirical work essential; computations generate conjectures and their results are often our best judge of the truth.
The semester will include three workshops that will concentrate on different aspects of current interest, including unusual settings such as complex networks and quasicrystals, the onset of emergence as small systems grow, and the emergence of structure and shape as limits in probabilistic models. The workshops will (necessarily) bring in researchers in combinatorics and probability as well as statistical physics and related areas. We aim to have experimental contributors for workshops 1 and 2 where we will highlight the comparison between computational and theoretical modeling and the real world. This will be combined with computational modules for the student participants. |

Weblink | http://icerm.brown.edu/sp-s15 |

Related subject(s) | Courses and Events for Math Students |

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14.ICERM Workshop: Crystals, Quasicrystals and Random Networks |

Dates | 09 Feb 2015 → 13 Feb 2015 | [ID=592218] |

Location | Providence, United States |

Abstract | The prototypical emergent phenomena are the bulk 'phases' of large collections of molecules, such as the fluid and solid phases. The solid phase is understood to emerge from an energy minimizing ideal crystal by the addition of random defects as energy increases from its minimum, the crucial/amazing fact being that the phase preserves something from the ideal crystal that unambiguously distinguishes it from the fluid phase. In this workshop we will focus on two significant variants of this classic picture: quasicrystals, and complex networks/random graphs. The analogue of energy minimizing crystals for quasicrystals are aperiodic tilings, such as the kite and dart tilings of Penrose, and for complex networks the analogue of energy minimizing crystals are (multi-partite) extremal graphs, graphs which minimize the number of subgraphs of some type. The workshop will focus on extremal graphs and aperiodic tilings and on the 'solid' phases they are believed to yield when random defects are introduced. It is hoped that progress can be made by pooling the expertise of researchers interested in the various aspects of these subjects. |

Weblink | http://icerm.brown.edu/sp-s15-w1 |

Related subject(s) | Applied Maths: Complex Networks |

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15.ICERM Workshop: Small Clusters, Polymer Vesicles and Unusual Minima |

Dates | 16 Mar 2015 → 20 Mar 2015 | [ID=592228] |

Location | Providence, United States |

Abstract | This workshop will explore emergent phenomena in the context of small clusters, supramolecular self-assembly and the shape of self-assembled structures such as polymer vesicles. The emphasis will be on surprises which arise when common conditions are not satisfied, for instance when the number of components is small, or they are highly non-spherical, or there are several types of components. Interactions vary from hard sphere repulsion to competition between coarse-grained liquid-crystalline ordering competing with shape deformation. Examples of this behavior are common in materials such as bulk homopolymers (rubber), copolymers, liquid crystals and colloidal aggregates. A basic mathematical setting would be to consider small clusters of hard spheres with isotropic short-range attractions and study the shape of the clusters as a function of the number of components. One known surprise is that highly symmetric structures are suppressed by rotational entropy. This emphasizes the need to accurately count the number of particle configurations that lead to the same final state. Small clusters can also generate anisotropic building blocks which can in turn serve as nano- or meso-scale building blocks for supermolecules and bulk materials (supramolecular chemistry) freed from the limited scope of atoms and quantum-mechanical bonding. These structures frequently possess topological defects in their ground states because they lower the energy. The challenge is to determine the shape and equilibrium defect structure of such superatoms and the number and geometry of their arrangement. The number of defects determines the effective valence of the super atoms and the global geometry of their arrangement determines the types of directional bonding possible when defects are linked together. The phenomenon of the appearance of singularities/defects because they are minimizers not necessarily required by topology or boundary conditions is also encountered in the study of harmonic maps. Moving up to self-assembly of large numbers of units, block copolymers self-assemble into a wide variety of structures including vesicles, nano-fibers and tori. Many of the structures formed are essentially two-dimensional surfaces embedded in R3. The mathematical challenge is to find both the shape and the order of the assembled object. This requires minimizing of a functional that depends on both the local and global order of the relevant matter fields and the shape of the surface. |

Weblink | http://icerm.brown.edu/sp-s15-w2 |

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16.ICERM Workshop: Limit Shapes |

Dates | 13 Apr 2015 → 17 Apr 2015 | [ID=592238] |

Location | Providence, United States |

Abstract | Since the days of Boltzmann, it has been well accepted that natural phenomena, when described using tools of statistical mechanics, are governed by various "laws of large numbers." For practitioners of the field this usually means that certain empirical means converge to constants when the limit of a large system is taken. However, evidence has been amassed that such laws apply also to geometric features of these systems and, in particular, to many naturally-defined shapes. Earlier examples where such convergence could be proved include certain interacting particle systems, invasion percolation models and spin systems in equilibrium statistical mechanics.
The last decade has seen a true explosion of "limit-shape" results. New tools of combinatorics, random matrices and representation theory have given us new models for which limit shapes can be determined and further studied: dimer models, polymer models, sorting networks, ASEP (asymmetric exclusion processes), sandpile models, bootstrap percolation models, polynuclear growth models, etc. The goal of the workshop is to attempt to confront this "ZOO" of combinatorial examples with older foundational work and develop a better understanding of the general limit shape phenomenon. |

Weblink | http://icerm.brown.edu/sp-s15-w3 |

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