We characterize obstruction sets in caterpillar dualities in terms of regular languages, and give a construction of the dual of a regular family of caterpillars. In particular, we prove that every monadic linear Datalog program with at most one EDB per rule defines the complement of a contraint satisfaction problem.

The reciprocal complementary Wiener number of a connected graph G is defined as ( ) { } ( ) ( ) | ∑ u v V G RCW G d d u v G ⊆ = + − , 1 1 , where ( ) V G is the vertex set. ( ) | d u v G , is the distance between vertices u and v, and d is the diameter of G. A tree is known as a caterpillar if the removal of all pendant vertices makes it as a path. Otherwise, it is called a non-caterpillar. Amo...

Common mycorrhizal networks (CMNs) link multiple plants together. We hypothesized that CMNs can serve as an underground conduit for transferring herbivore-induced defence signals. We established CMN between two tomato plants in pots with mycorrhizal fungus Funneliformis mosseae, challenged a 'donor' plant with caterpillar Spodoptera litura, and investigated defence responses and insect resistan...

In the heavy manufacturing industry, strength, resilience, and reliability are vital characteristics in products. In the early 1990s, Caterpillar developed a research plan to apply functionally gradient material (FGM) coatings onto wear parts in a cost-effective manner so that the coated parts would last several times longer than parts currently available. By spraying a series of coatings desig...

There are two main paradigms for querying semi structured data: regular path queries and XPath. The aim of this paper is to provide a synthesis between these two. This synthesis is given by a small addition to tree walk automata and the corresponding caterpillar expressions. These are evaluated on unranked finite sibling-ordered trees. At the expression level we add an operator whose meaning is...

The oak processionary caterpillar (Thaumetopoea processionea Lepidoptera) is found in several European countries. It usually lives in oak forests or on single-standing oak trees. The larva of from the 3rd to 6th developmental stage (instar) develops poisonous hair (setae), filled with an urticating toxin that may lead to serious dermatitis, conjunctivitis, and pulmonary affection (summarized as...

Given an undirected graph G and an integer k ≥ 0, the NPhard 2-Layer Planarization problem asks whether G can be transformed into a forest of caterpillar trees by removing at most k edges. Since transforming G into a forest of caterpillar trees requires breaking every cycle, the size f of a minimum feedback edge set is a natural parameter with f ≤ k. We improve on previous fixed-parameter tract...