Recent work shows that the memory requirements of bestfirst heuristic search can be reduced substantially by using a divide-and-conquer method of solution reconstruction. We show that memory requirements can be reduced even further by using a breadth-first instead of a best-first search strategy. We describe optimal and approximate breadth-first heuristic search algorithms that use divide-and-c...

Designing appropriate materials and activities to enhance vocabulary learning is one of the primary goals of language courses. Among the claims about efficient pedagogical tasks is the Involvement Load Hypothesis (Laufer & Hulstijn, 2001) according to which vocabulary development is contingent on the amount of cognitive process a task involves. Building on the previous research on this hypothes...

abstractthis study investigated the effect of digital games on vocabulary acquisition of low-proficiency iranian male and female efl learners. in order to select homogeneous learners in terms of their english language proficiency, the standard nelson proficiency test was administered, and based on the obtained results, 60 low-proficiency efl learners were selected (31 females and 29 males). the...

this study investigates the effect of different types of subtitle on incidental vocabulary learning among iranian efl learners. to this end, 60 high school students in behbahan were selected after taking a proficiency test. the test was administered to ensure participants' homogeneity. participants were randomly assigned to three experimental groups, namely, bimodal group (a), standard gro...

this study was an attempt to investigate whether teaching critical reading strategies had any significant effect on intermediate efl learners’ vocabulary retention. to fulfill the purpose of this study, 72 male and female students within the age range of 17 to 32 years studying at farzan and farzanegan language schools in tehran at intermediate level were selected from a total number of 114 par...

A 1984 problem of S. Z. Ditor asks whether there exists a lattice of cardinality א2, with zero, in which every principal ideal is finite and every element has at most three lower covers. We prove that the existence of such a lattice follows from either one of two axioms that are known to be independent of ZFC, namely (1) Martin’s Axiom restricted to collections of א1 dense subsets in posets of ...

In their 2009 paper, Corneil et al. design a linear time interval graph recognition algorithm based on six sweeps of Lexicographic Breadth-First Search (LBFS) and prove its correctness. They believe that their corresponding 5-sweep LBFS interval graph recognition algorithm is also correct. Thanks to the LBFS structure theory established mainly by Corneil et al., we are able to present a 4-sweep...

Recently lexicographic breadth first search (LexBFS) has been shown to be a very powerful tool for the development of linear time, easily implementable recognition algorithms for various families of graphs. In this paper, we add to this work by producing a simple two LexBFS sweep algorithm to recognize the family of cographs. This algorithm extends to other related graph families such as P4-red...