Reading Group - Computational Geometry

The aim of this reading group is to read some of the new and old literature in computational geometry, to get a firm grip on the various techniques that are commonly used in the field. The group meets regularly every week and a paper of interest is presented over a few two-three hour sessions by a member of the group. These sessions are also occasionally attended by other students and faculty that might be interested in the topic. If you are at IISc, and wish to attend these sessions, please contact one of the group members.

Sessions

Date Speaker Paper Title Topics Covered
May 16, 2023 Siddhartha Sarkar Weighted Geometric Set Cover via Quasi-Uniform Sampling
  • Quasi-uniform sampling technique
  • O(logloglog n)-approximate set cover for fat triangles
  • Union complexity
May 23, 2023 Mohit Garg Coloring and Maximum Weight Independent Set of Rectangles
  • O(w^2)-coloring for rectangles
  • O(w)-coloring of rectangles with only special types of intersections
May 30, 2023
  • Hierarchical decomposition
  • O(w)-coloring of rectangles with only special types of intersections
June 06, 2023 Aditya Subramanian Almost Optimal Set Covers in Finite VC-Dimension
  • Shattering dimension
  • O(dlog OPT)-approx for set cover with VC-dim = d
June 12, 2023 Rachana Gusain Persistent data structures
June 20, 2023 Nikhilesh Rajaraman Online and Dynamic Algorithms for Set Cover
  • Stable set covers
  • Greedy algorithm through an alternate lens
  • Dynamically maintaining set/element levels
June 28, 2023
  • Analysis using charging argument
July 04, 2023
  • Primal-dual analysis through charging using budgets
July 18, 2023 Debajyoti Kar Near-Linear Algorithms for Geometric Hitting Sets and Set Covers
  • Zero sum games
  • Approximate Nash Equilibrium using MWU
  • O(loglog OPT)-approximation for hitting set for rectangles
  • BST, Segment tree
July 25, 2023 Pranjal Singh (guest) Independence number of intersection graphs of axis-parallel segments
  • Favorable representation
  • Erdos-Szekeres theorem
August 02, 2023 Siddhartha Sarkar Approximation Algorithms for Maximum Independent Set of Pseudo-Disks
  • Local search analysis using union complexity
  • Frederickson’s planar separator theorem
  • PTAS for MIS on Pseudodisks
August 08, 2023
  • Resistance
  • Clarkson’s technique
  • u(n)/n-approximation for weighted geometric MIS
August 17, 2023 Mohit Garg Computing the Independence Number of Intersection Graphs
  • Separators in string graphs
  • Exact algorithms for MIS on string graphs
August 24, 2023 Aditya Subramanian Hitting sets online and unique max-coloring
  • Vertex ranking
  • Theta(log n)-approximation for online hitting sets on intervals
  • Chen et al.’s Plane partitioning technique
August 31, 2023
  • Theta(log n)-approximation for online hitting sets on unit disks
September 05, 2023 Rachana Gusain Dynamic Approximate Maximum Independent Set of Intervals, Hypercubes and Hyperrectangles
  • Hierarchical grid decomposition
  • Data structure to report smallest hypercube inside a box
September 12, 2023
  • Dynamic DP over hierarchical grid
  • Analysis of greedy algorithm via charging
  • (1+eps).2^d-approximation in polylog update time for dynamic MIS on hypercubes
October 03, 2023 Nikhilesh Rajaraman On Dynamic Graph Algorithms with Predictions
  • Dynamic All Pairs Shortest Paths (APSP) with predictions
October 26, 2023
  • Dynamically maintaining matrix inverse with column updates in O(n^2) time
  • Woodbury matrix identity
  • Dynamic s-t connectivity in O(n^2) update time
October 12, 2023 Debajyoti Kar Online Independent Set Beyond the Worst-Case: Secretaries, Prophets, and Periods
  • Inductive independence number
  • 8.rho^2-approximation for unweighted MIS in Secretary model
October 19, 2023
  • O(rho^2 log n)-approximation for weighted MIS in Secretary model
  • Omega(log n/(loglog n)^2) lower bound
November 11, 2023 Aditya Subramanian Tight Bounds for Online Weighted Tree Augmentation
  • Caterpillar decomposition
  • Rooted path decomposition of width O(log n)
December 07, 2023
  • Suboptimal O(log^2 n)-approximation for online WTAP
  • Strategy to get O(log n)-approximation using “nice” feasible solution of WPAP
  • LP relaxation for online WPAP
December 12, 2023
  • Omega(log n) lower bound for online WPAP
  • Omega(log n) lower bound for online (unweighted) TAP
January 25, 2024
  • Overview of O(log n) online WPAP
  • Proof of niceness via duality
January 30, 2024
  • Nice algorithm for WPAP
February 09, 2024 Siddhartha Sarkar Packing and Covering with Non-Piercing Regions
  • Lens Bypassing to characterize non-piercing regions
  • Locality preserving property
  • Outline of algorithm using planar separators
February 20, 2024
  • Construction of locality preserving graph

Members

rajaraman

Nikhilesh Rajaraman

rachana

Rachana Gusain

siddhartha

Siddhartha Sarkar

Faculty Advisors