Tree-width is a well-known metric on undirected graphs that measures how tree-like a graph is and gives a notion of graph decomposition that proves useful in algorithm development. Tree-width is characterised by a game known as the cops-and-robber game where a number of cops chase a robber on the graph. We consider the natural adaptation of this game to directed graphs and show that monotone st...

The question of the exact complexity of solving parity games is one of the major open problems in system verification, as it is equivalent to the problem of model-checking the modal mu-calculus. The known upper bound is NP intersection co-NP, but no polynomial algorithm is known. It was shown that on tree-like graphs (of bounded tree-width and DAG-width) a polynomial-time algorithm does exist. ...

Let A be finite relational structure of finite type, and let CSP (A) denote the following decision problem: if I is a given structure of the same type as A, is there a homomorphism from I to A ? To each relational structure A is associated naturally an algebra A whose structure determines the complexity of the associated decision problem. We investigate those finite algebras arising from CSP’s ...

In this paper, properties of slab deformation in sizing press mill as one of the slab reduction processes in hot rolling mills have been evaluated using the elastoviscoplastic finite element method with explicit formulation. Effect of prarameters such as initial slab width and thickness, reduction, feed pitch, and anvil speed on factors such as dogbone formation, head and tail fishtail profile,...

Introduction: Since palmaris longus tendon is the first choice for grafting, its anatomical variation is important. This study was designed to find the anatomical variations of this tendon in Iranian population by performing a study on cadaver. Method: In this study, 150 forearms belonged to 75 cadavers were studied. After exploring the proximal end of tendon, tendon width was measured at its p...