• Going Far From Degeneracy 

      Fomin, Fedor; Golovach, Petr; Lokshtanov, Daniel; Panolan, Fahad; Saurabh, Saket; Zehavi, Meirav (Peer reviewed; Journal article, 2019-09-06)
      An undirected graph G is d-degenerate if every subgraph of G has a vertex of degree at most d. By the classical theorem of Erd\H{o}s and Gallai from 1959, every graph of degeneracy d>1 contains a cycle of length at least ...
    • Hitting Topological Minor Models in Planar Graphs is Fixed Parameter Tractable 

      Golovach, Petr; Thilikos, Dimitrios; Stamoulis, Giannos (Journal article; Peer reviewed, 2020)
      For a finite collection of graphs F, the F-TM-Deletion problem has as input an n-vertex graph G and an integer k and asks whether there exists a set S ⊆ V(G) with |S| ≤ k such that G \ S does not contain any of the graphs ...
    • How to find a good explanation for clustering? 

      Bandyapadhyay, Sayan; Fomin, Fedor; Golovach, Petr; Lochet, William Alexandre; Purohit, Nidhi; Simonov, Kirill (Journal article; Peer reviewed, 2023)
      k-means and k-median clustering are powerful unsupervised machine learning techniques. However, due to complicated dependencies on all the features, it is challenging to interpret the resulting cluster assignments. Moshkovitz, ...
    • Kernelization of Graph Hamiltonicity: Proper H-Graphs 

      Chaplick, Steven; Fomin, Fedor; Golovach, Petr; Knop, Dusan; Zeman, Peter (Journal article; Peer reviewed, 2021)
      We obtain new polynomial kernels and compression algorithms for Path Cover and Cycle Cover, the well-known generalizations of the classical Hamiltonian Path and Hamiltonian Cycle problems. Our choice of parameterization ...
    • Kernelization of Whitney Switches 

      Fomin, Fedor; Golovach, Petr (Journal article; Peer reviewed, 2020)
      A fundamental theorem of Whitney from 1933 asserts that 2-connected graphs G and H are 2-isomorphic, or equivalently, their cycle matroids are isomorphic, if and only if G can be transformed into H by a series of operations ...
    • Kernelization of Whitney Switches 

      Fomin, Fedor; Golovach, Petr (Journal article; Peer reviewed, 2021)
      A fundamental theorem of Whitney from 1933 asserts that 2-connected graphs $G$ and $H$ are 2-isomorphic, or equivalently, their cycle matroids are isomorphic if and only if $G$ can be transformed into $H$ by a series of ...
    • Long Cycles in Graphs: Extremal Combinatorics Meets Parameterized Algorithms 

      Fomin, Fedor; Golovach, Petr; Sagunov, Danil; Simonov, Kirill (Journal article; Peer reviewed, 2022)
      We discuss recent algorithmic extensions of two classic results of extremal combinatorics about long paths in graphs. First, the theorem of Dirac from 1952 asserts that a 2-connected graph G with the minimum vertex degree ...
    • Longest Cycle Above Erdös-Gallai Bound 

      Fomin, Fedor; Golovach, Petr; Sagunov, Danil; Simonov, Kirill (Journal article; Peer reviewed, 2022)
      In 1959, Erdős and Gallai proved that every graph G with average vertex degree ad(G) ≥ 2 contains a cycle of length at least ad(G). We provide an algorithm that for k ≥ 0 in time 2^𝒪(k)⋅n^𝒪(1) decides whether a 2-connected ...
    • Lossy Kernelization of Same-Size Clustering 

      Bandyapadhyay, Sayan; Fomin, Fedor; Golovach, Petr; Purohit, Nidhi; Simonov, Kirill (Journal article; Peer reviewed, 2023)
      In this work, we study the k-median clustering problem with an additional equal-size constraint on the clusters from the perspective of parameterized preprocessing. Our main result is the first lossy (2-approximate) ...
    • Low-Rank Binary Matrix Approximation in Column-Sum Norm 

      Fomin, Fedor; Golovach, Petr; Panolan, Fahad; Simonov, Kirill (Journal article; Peer reviewed, 2020)
      We consider 𝓁₁-Rank-r Approximation over {GF}(2), where for a binary m× n matrix 𝐀 and a positive integer constant r, one seeks a binary matrix 𝐁 of rank at most r, minimizing the column-sum norm ‖ 𝐀 -𝐁‖₁. We show ...
    • Modification to planarity is fixed parameter tractable 

      Fomin, Fedor; Golovach, Petr; Thilikos, Dimitrios M (Peer reviewed; Journal article, 2019)
      A replacement action is a function L that maps each k-vertex labeled graph to another k-vertex graph. We consider a general family of graph modification problems, called L-Replacement to C, where the input is a graph G and ...
    • On the Complexity of Recovering Incidence Matrices 

      Fomin, Fedor; Golovach, Petr; Misra, Pranabendu; Ramanujan, M.S. (Journal article; Peer reviewed, 2020)
      The incidence matrix of a graph is a fundamental object naturally appearing in many applications, involving graphs such as social networks, communication networks, or transportation networks. Often, the data collected about ...
    • On the Tractability of Optimization Problems on H-Graphs 

      Fomin, Fedor; Golovach, Petr; Raymond, Jean-Florent (Journal article; Peer reviewed, 2020)
      For a graph H, a graph G is an H-graph if it is an intersection graph of connected subgraphs of some subdivision of H. H-graphs naturally generalize several important graph classes like interval graphs or circular-arc ...
    • Parameterization Above a Multiplicative Guarantee 

      Fomin, Fedor; Golovach, Petr; Lokshtanov, Daniel; Panolan, Fahad; Saurabh, Saket; Zehavi, Meirav (Journal article; Peer reviewed, 2020)
      Parameterization above a guarantee is a successful paradigm in Parameterized Complexity. To the best of our knowledge, all fixed-parameter tractable problems in this paradigm share an additive form defined as follows. Given ...
    • Parameterized complexity of categorical clustering with size constraints 

      Fomin, Fedor; Golovach, Petr; Purohit, Nidhi (Journal article; Peer reviewed, 2023)
    • Parameterized Complexity of Directed Spanner Problems 

      Fomin, Fedor; Golovach, Petr; Lochet, William; Misra, Pranabendu; Saurabh, Saket; Sharma, Roohani (Journal article; Peer reviewed, 2020)
      We initiate the parameterized complexity study of minimum t-spanner problems on directed graphs. For a positive integer t, a multiplicative t-spanner of a (directed) graph G is a spanning subgraph H such that the distance ...
    • Parameterized Complexity of Directed Spanner Problems 

      Fomin, Fedor; Golovach, Petr; Lochet, William Alexandre; Misra, Pranabendu; Saurabh, Saket; Sharma, Roohani (Journal article; Peer reviewed, 2021)
      We initiate the parameterized complexity study of minimum t-spanner problems on directed graphs. For a positive integer t, a multiplicative t-spanner of a (directed) graph G is a spanning subgraph H such that the distance ...
    • Parameterized Complexity of Feature Selection for Categorical Data Clustering 

      Bandyapadhyay, Sayan; Fomin, Fedor; Golovach, Petr; Simonov, Kirill (Journal article; Peer reviewed, 2021)
      We develop new algorithmic methods with provable guarantees for feature selection in regard to categorical data clustering. While feature selection is one of the most common approaches to reduce dimensionality in practice, ...
    • Parameterized complexity of PCA 

      Fomin, Fedor; Golovach, Petr; Simonov, Kirill (Journal article; Peer reviewed, 2020)
      We discuss some recent progress in the study of Principal Component Analysis (PCA) from the perspective of Parameterized Complexity.
    • Parameterized complexity of secluded connectivity problems 

      Fomin, Fedor; Golovach, Petr; Karpov, Nikolay; Kulikov, Alexander S (Peer reviewed; Journal article, 2015)
      The Secluded Path problem introduced by Chechik et al. in [ESA 2013] models a situation where a sensitive information has to be transmitted between a pair of nodes along a path in a network. The measure of the quality of ...