Article révisé par les pairs
Résumé : The input of the Tropical Connected Set problem is a vertexcolored graph G = (V, E) and the task is to find a connected subset S ⊆ V of minimum size such that each color of G appears in S. This problem is known to be NP-complete, even when restricted to trees of height at most three. We show that Tropical Connected Set on trees has no subexponential-time algorithm unless the Exponential Time Hypothesis fails. This motivates the study of exact exponential algorithms to solve Tropical Connected Set. We present an O∗(1.5359n) time algorithm for general graphs and an O∗(1.2721n) time algorithm for trees.