Applied Algebraic Topology (AAT) network in the UK

Next meeting of the Applied Algebraic Topology network
 The next meeting is planned in Southampton, not earlier than April 2019.
 In November 2018 the London Mathematical Society has extended the funding for two more years until 2020.
 If you would like to offer a talk at the next AAT meeting, please email the title and abstract to one of local organisers.
 The London Mathematical Society partially covers local travel and accommodation of participants of the AAT meetings.
Organisers of the Applied Algebraic Topology network
 Dr Ginestra Bianconi (ginestra.bianconi at gmail.com), Queen Mary University of London
 Prof Jacek Brodzki (j.brodzki at soton.ac.uk), University of Southampton
 Prof Michael Farber (m.farber at qmul.ac.uk), Queen Mary University of London
 Dr Ana GarciaPulido (a.l.garciapulido at liverpool.ac.uk), University of Liverpool
 Prof Jelena Grbić (j.grbic at soton.ac.uk), University of Southampton
 Dr Vitaliy Kurlin (vitaliy.kurlin at gmail.com), University of Liverpool.
Past meetings of the Applied Algebraic Topology network
 The 12th meeting was on Monday 4th February 2019 in Queen Mary University of London: schedule in pdf.
 10.0010.45 Primoz Skraba (QMUL) Computing Persistence in Parallel
 10.4511.30 Jon Woolf (Liverpool) Stratified Homotopy Theory
 11.4512.30 Tomaso Aste (UCL) Learning Clique Forests for Probabilistic Modeling
 14.00  14.45 Tahl Nowik (Bar Ilan University) Random knots
 14.55  15.40 Ian Leary (Southampton) Examples for Brownâ€™s question(s) on dimensions of groups
 The 11th meeting was combined with the TDA workshop organised by Dr Vitaliy Kurlin at MFCS on Friday 31st August 2018 in the Materials Innovation Factory (3rd floor meeting room, building 807, square 5F on the campus map), Liverpool, UK.
The attendance is free, please sign in at the reception and email Dr Vitaliy Kurlin for catering purposes.
 14.0014.45 Dr Hubert Wagner (IST Austria)
Title. Computing persistent homology of images with Cubicle.
Abstract. Persistent homology is gaining popularity for analyzing data coming from medical imaging, astrophysics and material science. I will focus on novel techniques for computing persistent homology of multidimensional images. In particular, I will address the eternal question: "To use, or not to use (discrete Morse theory)". A new software package, Cubicle, will be showcased and compared with existing packages.  15.1516.00 Ms Katharina Oelsboeck (IST Austria)
Title. Shape Reconstruction with Holes.
Abstract. We want to reconstruct the shape of a point clould, with focus on the holes of the resulting model. In many cases, the alpha complex of appropriate scale gives a good reconstruction. However, in some applications the holes of the model are important and there is no scale of the alpha complex that gives a satisfactory result.We define operations to change the birth and death of holes in a filtered simplicial complex, i.e., they open or close holes in a subcomplex of a fixed scale. A tripartition of the simplices, and canonical (co)chains and (co)cycles that are associated to the simplices will help us identify for which simplices we need to adapt their filtration values. These can be computed with a specific matrix reduction algorithm for persistent homology. The persistence diagram of the complex can help us guide the application of the hole operations. In the second part, we will present the Wrap complex as an alternative for shape reconstruction and will apply the hole operations on it.  16.3017.15 Mr Philip Smith (MIF, Liverpool)
Title. Skeletonization algorithms with theoretical guarantees for unorganized point clouds.
Abstract. We study the problem of approximating an unorganized cloud of points (in any Euclidean or metric space) by a 1dimensional graph or a skeleton. The following recent algorithms provide theoretical guarantees for an output skeleton: the 1dimensional Mapper, alphaReeb graphs and a Homologically Persistent Skeleton. All the three algorithms will be introduced on simple examples and then experimentally compared on the same synthetic and real data. The synthetic data are random point samples around planar graphs and sets of edge pixels obtained by a Canny edge detector on images from the Berkeley Segmentation Database BSD500. The criteria for comparison are the running time, topological types, geometric errors of reconstructed graphs.
 14.0014.45 Dr Hubert Wagner (IST Austria)

 The 10th meeting was on 30th April 2018 at the University of Southampton.
 10:3011:20 Rachel Jeitziner (EPFL) TwoTier Mapper: a userindependent clustering method for global gene expression analysis based on topology
 11:3012:00 Mariam Pirashvili (Southampton) Improved understanding of aqueous solubility modeling through Topological Data Analysis
 14:0014:50 Ginestra Bianconi (QMUL) Emergent Hyperbolic Network Geometry and Frustrated Synchronization
 15:0015:50 Grzegorz Muszynski (Liverpool) Topological Analysis and Machine Learning for Detecting Atmospheric River Patterns in a Climate Model Output

 The 9th meeting was on 2nd February 2018 in the Queen Mary University of London.
 9.3010.30 (Scape 1.04) Prof Gabor Elek (University of Lancaster) Topological graph limits
 11.0012.00 (Scape 1.04) Dr Tim Evans (Imperial College London) Networks and Spacetime
 14.0015.00 (Scape 2.01) Prof Ran Levi (Aberdeen) NeuroTopology: An interaction between topology and neuroscience
 15.3016.30 (Scape 2.01) Dr Stephan Mescher (University of Leipzig) Topological complexity of aspherical spaces
 The network was initiated by Prof Michael Farber (Queen Mary) with coorganisers at Aberdeen, Durham, Southampton.
 The first 8 meetings were in 20152016 at Aberdeen, Durham, Queen Mary, Southampton.
 The previous webpage was excellently maintained by Dr Mark Grant (Aberdeen).
Research topics of the Applied Algebraic Topology network
We run 3 halfday meetings per year with 34 talks on many topics of applied topology including (but not restricted to)
 Topology of configuration spaces of particles and mechanisms of different types (including linkages) and their applications in robotics, molecular biology and materials chemistry.
 Topology of robot motion planning, complexity of algorithms for autonomous robot motion.
 Stochastic topology (random complexes, random manifolds, random groups etc).
 Applications of Topological Data Analysis to Computer Vision, Materials Science, Climate system, pattern recognition and reconstruction of persistent topological structures in big and noisy data.
 Combinatorial and toric homotopy theory (simplicial complexes and polytopes, momentangle complexes, polyhedral products, etc).