We consider the Cauchy problem for a hyperbolic pseudodifferential operator whose symbol is generalized, resembling a representative of a Colombeau generalized function. Such equations arise, for example, after a reduction-decoupling of second-order model systems of differential equations in seismology. We prove existence of a unique generalized solution under logtype growth conditions on the s...

This paper is concerned with the status of a symbol in Wittgenstein’s Tractatus. It is claimed in the first section that a Tractarian symbol, whilst essentially a syntactic entity to be distinguished from the mark or sound that is its sign, bears its semantic significance only inessentially. In the second and third sections I pursue this point of exegesis through the Tractarian discussions of n...

It is generally recognized that the common nonterminal labels for syntactic constituents (NP, VP, etc.) do not exhaust the syntactic and semantic information one would like about parts of a syntactic tree. For example, the Penn Treebank gives each constituent zero or more ‘function tags’ indicating semantic roles and other related information not easily encapsulated in the simple constituent la...

We experiment with adding semantic role information to a string-to-tree machine translation system based on the rule extraction procedure of Galley et al. (2004). We compare methods based on augmenting the set of nonterminals by adding semantic role labels, and altering the rule extraction process to produce a separate set of rules for each predicate that encompass its entire predicate-argument...

This paper studies the nonterminal complexity of tree controlled grammars. It is proved that the number of nonterminals in tree controlled grammars without erasing rules leads to an infinite hierarchy of families of tree controlled languages, while every recursively enumerable language can be generated by a tree controlled grammar with erasing rules and at most nine nonterminals. © 2011 Elsevie...

For tabled Lindenmayer systems and their languages, the degree of synchronization and the degree of nondeterminism are well investigated measures of descriptional complexity. In this paper the sequential counterparts of tabled Lindenmayer systems, namely cooperating distributed grammar systems and their pure variant (working in the so called t-mode of derivation) are treated with respect to the...

Given an undirected graph and pairs of terminals theRestricted Vertex Multicut problem asks for a minimum set of nonterminal vertices whose removal disconnects each pair of terminals. The problem is known to be NP-complete for trees and polynomial-time solvable for interval graphs. In this paper we give a polynomial-time algorithm for the problem on permutation graphs. Furthermore we show that ...

This paper presents new models for all recursive enumerable languages. These models are based on multigenerative grammar systems that simultaneously generate several strings in a parallel way. The components of these models are context -free grammars, working in a leftmost way. The rewritten nonterminals are determined by a finite set of nonterminal sequences.

in during contemporary, its few of artists for numerous changes in artistic creation who have cared to reproduce some special symbols. in fact, these symbols are minor contain to the beliefs, cultures and values of people in the country. one of the most important artists is jazeh tabatabaie, painter and sculptor, devoting significant share to review of symbols. he recreated some of the symbols ...

Computer-assisted language learning (CALL) is reaching an up most position in the pedagogical field of English as a Second or Foreign Language (ESL/EFL). The present study was carried out to study the effect of using phonetic websites on Iranian EFL students’ pronunciation and knowledge of phonemic symbols. Participants of the study included 30 EFL female pre-intermediate students studyin...