Close to 30 percent of all patents are chemical patents, of which roughly 10 percent claim IP rights over novel chemical structures using the Markush notation[1-5]. An example of an approved patent with claims on a series of 4-anilino-3-quinolinecarbonitriles-based chemical structures for the

2. Formal languages

Abstract: By introducing a new operation, the exponentiation of formal languages, we can define Heyting algebras of formal languages. It turns out that some well known families of languages are closed under this exponentiation, e. g., the families of regular and of context-sensitive languages.

In this paper, we advocate a study of analogies between strings of symbols for their own sake. We show how some sets of strings, i.e., some formal languages, may be characterized by use of analogies. We argue that some preliminary \good properties" obtained may plead in favour of the use

This article provides an introduction to the theory of automata and formal languages. The elements are presented in a historical perspective and the links with other areas are underlined. In particular, applications of the field to linguistics, software design, text processing, computational

-theoretic interpretation and proof of a key theorem of Chomsky and Schützenberger from formal language theory. 1.

. I survey some of the connections between formal languages and number theory. Topics discussed include applications of representation in base k, representation by sums of Fibonacci numbers, automatic sequences, transcendence in finite characteristic, automatic real numbers, fixed points

in the theory of natural languages. Here it is shown that formal languages too can be specified by Harmonic Grammars, rather than by conventional serial re-write rule systems.

We survey recent results on the enumeration of formal languages. In particular, we consider enumeration of regular languages accepted by deterministic and nondeterministic finite automata with n states, regular languages generated by regular expressions of a fixed length, and ω-regular languages

We consider classes of sets of r-adic expansions of reals specified by means of the theory of formal languages or automata theory. It is shown how these specifications are used to calculate the Hausdorff dimension and Hausdorff measure of such sets. Since the appearence of Mandelbrot's 11