Strings, graphs, invariants

Strings play an important role in various sciences, from computer science, linguistics, social sciences, to various natural sciences, including bioinformatics. Strings, words, or finite sequences are mainly studied in formal language theory and form the basis of logic, mathematics and theoretical computer science. Although strings have a simple linear structure, we may associate a number of invariants to them in particular, via various graphs. This non-technical talk will explain some of these features and survey some of the recent work of the present authors. 123