Some Undecidability Results for Finitely Generated Thue Congruences on aTwo-Letter Alphabet

A Class of Two Generated Automaton Groups on a Three Letter Alphabet

Overlap-Free Words and Generalizations

The study of combinatorics on words dates back at least to the beginning of the 20 century and the work of Axel Thue. Thue was the first to give an example of an infinite word over a three letter alphabet that contains no squares (identical adjacent blocks) xx. This result was eventually used to solve some longstanding open problems in algebra and has remarkable connections to other areas of ma...

The effects of teaching English alphabet with and without initial introduction of letter names on Iranian grade seven students' reading speed

One of the most important steps in teaching English is teaching its alphabet to the learners. Implementing the best method will highly help teachers to achieve acceptable results in helping students to read better and faster. Two basic methods are frequently used by Iranian educators. Some start by the name of the letters and introduce the sounds that they symbolize later, while others are thos...

Preserving Regularity and Related Properties

A nite string-rewriting system R preserves regularity if and only if it preserves-regularity, where is the alphabet containing exactly those letters that have occurrences in the rules of R. This proves a conjecture of Gyenizse and VV agvv olgyi (1995). In addition, some undecidability results are presented that generalize some results of Gilleron and Ti-son (1995) from term-rewriting systems to...

An automaton group: a computational case study

We introduce a two generated weakly branch contracting automaton group $G$ which is generated by a two state automaton on a three letter alphabet. Using its branch structure and the finiteness nature of a sequence of its factor groups we compute the order of some of these factors. Furthermore some algebraic properties of $G$ are detected .