Asymmetric Traveling Salesman Path and Directed Latency Problems

Traveling salesman path problems

In the traveling salesman path problem, we are given a set of cities, traveling costs between city pairs and fixed source and destination cities. The objective is to find a minimum cost path from the source to destination visiting all cities exactly once. In this paper, we study polyhedral and combinatorial properties of a variant we call the traveling salesman walk problem, in which the object...

Asymmetric Traveling Salesman Problem

The asymmetric traveling salesman problem (ATSP) is one of the most fundamental problems in combinatorial optimization. An instance of ATSP is a directed complete graph G = (V,E) with edge weights w : E → N that satisfy the triangle inequality, i. e., w(a, c) ≤ w(a, b) +w(b, c) for all distinct vertices a, b, c ∈ V . The goal is to find a Hamiltonian cycle of minimum weight. The weight of a Ham...

The Asymmetric Traveling Salesman Problem

LP-Based Approximation Algorithms for Traveling Salesman Path Problems

We present a ( 3 − ǫ)-approximation algorithm for some constant ǫ > 0 for the traveling salesman path problem under the unit-weight graphical metric, and prove an upper bound on the integrality gap of the path-variant Held-Karp relaxation both under this metric and the general metric. Given a complete graph with the metric cost and two designated endpoints in the graph, the traveling salesman p...

Exact Graph Search Algorithms for Generalized Traveling Salesman Path Problems

The Generalized Traveling Salesman Path Problem (GTSPP) involves finding the shortest path from a location s to a location t that passes through at least one location from each of a set of generalized location categories (e.g., gas stations, grocery stores). This NP-hard problem type has many applications in transportation and location-based services. We present two exact algorithms for solving...