We analyze the structure of reduced expressions in the Coxeter groups An, Bn and Dn. Several special classes of elements are singled out for their connections with symmetric functions or the theory of P -partitions. Membership in these special classes is characterized in a variety of ways, including forbidden patterns, forbidden subwords, and by the form of canonically chosen reduced words.

We introduce and study a class of simplicial complexes, the orphan complexes, associated to simple graphs whose family of (open or closed) vertex-neighborhoods are anti-Sperner. Under suitable restrictions, we show that orphan complexes of such graphs are always shellable and provide a characterization of graphs in terms of induced forbidden subgraphs contained in this restricted subfamily.

In this paper we demonstrate that several theorems from [1] and [3] do not hold as they are stated. These are the theorems regarding forbidden subposet characterizations of certain classes of coverincomparability graphs. In this paper we correct a mistake in the main theorem of [1], reformulate the corresponding statements and present corrected proofs. We further characterize posets whose cover...

Technical Publication No. 2313 Class E, Metals Technology, January 1948 DISCUSSION OF THIS PAPER IS INVITED. It should preferably be presented by the contrihutqr in person at the New York Meeting. February 1948. when an abstract of the paper will be read. If this is imposs~ble, discussion in writing (a copies) may be sent to the Secretary. American Institute of Mining and Metallurgical Engrneer...

D. Malindžák, BERG Faculty, Technical University of Košice, Košice, Slovakia Metallurgical production processes (MPP) consist of continuous and discrete types of technology operation, transport, manipulation and storing processes regards the fl ow of material and also the equipment and machines. Other specifi cs are: long production cycles, great inertia, tree structure of production processes ...

processing of minerals and production of metals has increased greatly in recent years. as a result, the quantities of waste material and pollutants have also increased. in many cases technology has changed to cope with the problem. processes have been either modified to decrease emissions, or replaced by others that are less polluting even if at a higher cost. this paper briefly reviews example...

      Simulation of metallurgical processes has been the subject of intense research due to the reduced number of experiments required for controlling the process as well as time and energy savings it allows. In gas carburizing of steel parts, the amount of carbon at the surface of carburized parts is the most important specification of the process in terms of achieving the desired metallurgica...

ALADIN is an expert system that aids metallurgists in the design of new aluminum alloys. The project began in January 1984, and two major iterations of the system design have been completed. The current system is a hybrid of several approaches and artificial intelligence techniques. Declarative representations are used for metallurgical data and concepts. The basic design procedure is encoded i...