The derivational complexity of string rewriting systems

On String Rewriting Systems

String rewriting systems, also known as semi-Thue systems, consist of a set of rules l → r, specifying valid replacements of substrings of strings over a given alphabet. In the case of one single rule, it is an open problem whether there is a system that is neither terminating nor looping. Another open question is the decidability of termination. Difficulties arise especially for non-confluent ...

Observation of String-Rewriting Systems

In most models of computation, a device performs some type of process, and only some final output is regarded as the result. In adding an observer to such a device, one can obtain a protocol of the entire process and then use this as the computation’s result. In a series of articles this approach has proved to often exceed greatly the power of the system observed. Here we apply this architectur...

Peg - Solitaire , String Rewriting Systems

We consider a class of length-preserving string rewriting systems and show that the set of encodings of pairs of strings < s; f > such that f can be derived from s using the rewriting rules can be accepted by nite automata. As a consequence, we show the existence of a linear time algorithm for determining the solvability of a given k n peg-solitaire board, for any xed k. This result is in contr...

On the Complexity of a Problem on Monadic String Rewriting Systems

the effect of task complexity on lexical complexity and grammatical accuracy of efl learners’ argumentative writing

بر اساس فرضیه شناخت رابینسون (2001 و 2003 و 2005) و مدل ظرفیت توجه محدود اسکهان (1998)، این تحقیق تاثیر پیچیدگی تکلیف را بر پیچیدگی واژگان و صحت گرامری نوشتار مباحثه ای 60 نفر از دانشجویان زبان انگلیسی بررسی کرد. میزان پیچیدگی تکلیف از طریق فاکتورهای پراکندگی-منابع تعیین شد. همه ی شرکت کنندگان به صورت نیمه تصادفی به یکی از سه گروه: (1) گروه موضوع، (2) گروه موضوع + اندیشه و (3) گروه موضوع + اندی...