B. S. Galiukschov. Semicontextual grammars (in russian). Mat. Logica i Mat. Ling., pages 38--50, 1981.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....theory and combinatorics on words. We investigate a generative device of a type resembling certain somewhat exotic devices in formal language theory, not based on rewriting, as the Chomsky grammars and Lindenmayer systems are, but closer to Marcus grammars [7] 8] or Galiukschov grammars [2]. The main idea is depicted in figure 1. ae ae ae ae ae ae ae= I u v u v Figure 1 w w w 1 w 2 One gives a starting string and a finite set of insertion contexts (u; v) They can be considered weak links , where a string can be broken and relinked after adding a new segment. ....

.... not present such variants here, formal definitions can be found in the next section (for the various possibilities of answering question (2) We want, however, to stress the intimate connection between our snake replicating machines and the insertion operation in [6] the insertion grammars of [2] (based on rewriting rules of the form uv uxv) the splicing and crossover 1 operations specific to DNA recombination [4] 5] as well as to learning theory: we may assume that the strings we work with are representations of certain piece of knowledge, which is self enriched, longer and ....

B. S. Galiukschov, Semicontextual grammars, Mat. logica i mat. ling., Kalinin Univ., 1981, 38 -- 50 (in Russ.).

....etc. are based on the operation of rewriting, see, e.g. 13] 14] However, there are several classes of grammars whose basic ingredient is the adjoining operation. The most important of them are the tree adjoining grammars (TAG) 5] the contextual grammars ( 7] and the insertion grammars ([4]) all three introduced as models of constructions in natural languages. The insertion grammars (in [4] they are called semi contextual grammars) are somewhat intermediate between Chomsky context sensitive grammars (where the nonterminals are rewritten according to specified contexts) and Marcus ....

....of grammars whose basic ingredient is the adjoining operation. The most important of them are the tree adjoining grammars (TAG) 5] the contextual grammars ( 7] and the insertion grammars ( 4] all three introduced as models of constructions in natural languages. The insertion grammars (in [4] they are called semi contextual grammars) are somewhat intermediate between Chomsky context sensitive grammars (where the nonterminals are rewritten according to specified contexts) and Marcus contextual grammars (where contexts are adjoined to specified strings associated with contexts) In ....

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B. S. Galiukschov, Semicontextual grammars (in Russian), Mat. logica i mat. ling., Kalinin Univ., 1981, 38 -- 50.

.... system generates the elements of a language by inserting and deleting words, according to their contexts (the insertiondeletion rules are triples (u; z; v) with the meaning that z can be inserted or deleted in from the context (u; v) Grammars based on insertion rules were already considered in [6] with linguistic motivation. Insertion deletion operations are also basic in DNA and RNA processing, 2] Our results show that these operations, even with strong restrictions on the length of the contexts and or on the length or on the form of the inserted deleted words are computationally ....

....considered. In contextual grammars introduced in [12] up to dated details can be found in the forthcoming monograph [18] pairs of strings are inserted, depending on the bracketed string. A similar effect has the tree adjoining operation in TAG s, 8] A sort of dual model has been considered in [6]: strings are inserted in given associated contexts. In all these cases only context sensitive languages are obtained. A natural extension of these generative mechanisms is to consider also erasing operations. For contextual grammars this has been done in [19] Insertion deletion grammars, ....

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B. S. Galiukschov, Semicontextual grammars (in Russian), Mat. logica i mat. ling., Talinin Univ., 1981, 38 -- 50.

.... generates the elements of a language by inserting and deleting words, according to their contexts (the insertion deletion rules are triples (u; z; v) with the meaning that z can be inserted or deleted in from the context (u; v) Grammars based on insertion rules were already considered in [22] with linguistic motivation. Insertion deletion operations are also basic in DNA and RNA processing, 14] Our results show that these operations, even with strong restrictions on the length of the contexts and or on the length of the inserted deleted words are computationally complete, that is, ....

B.S.Galiukschov. Semicontextual grammars (in Russian). Mat.logica i mat. ling., Kalinin Univ., 1981, 38-50.

....insertions of oligonucleotide sequences are contextsensitive. Consequently, an attempt to better model the process is to use a modified notion of insertion so that insertion of a word takes place only if a certain context is present. This can be formalized by the notion of contextual insertion, [7], 12] 13] 16] Let (x; y) 2 X ThetaX be a pair of words called a context. The (x; y) contextual insertion of v 2 X into u 2 X is defined as: u (x;y) v = fu 1 xvyu 2 ju 1 ; u 2 2 X ; u = u 1 xyu 2 g: If the word u does not contain xy as a subword, the result of the (x; y) ....

B.S.Galiukschov. Semicontextual grammars (in Russian). Mat.logica i mat. ling., Kalinin Univ., 1981, 38-50.

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B. S. Galiukschov. Semicontextual grammars (in russian). Mat. Logica i Mat. Ling., pages 38--50, 1981.

No context found.

B. S. Galiukschov. Semicontextual grammars (in russian). Mat. Logica i Mat. Ling., pages 38--50, 1981.

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