String adjunct grammars: II. Equational representation, null symbols, and linguistic relevance

Similarities Between String Grammars and Graph Grammars

In this paper, we present some studies about relations existing between well known Chomsky string grammars and graph grammars, in particularly hypergraph grammars. We are discussing about deterministic context free Lindenmayer Systems used to describe commands to a device that generates black and white digital images. Instead of well-known methods of drawing, we will paint squares, not lines. A...

Properties of Formal Grammars with mixed Type of Rules and their Linguistic Relevance

Anisotropic Null String Cosmologies

We study string propagation in an anisotropic, cosmological background. We solve the equations of motion and the constraints by performing a perturbative expansion of the string coordinates in powers of c, the world-sheet speed of light. To zeroth order the string is approximated by a tensionless string (since c is proportional to the string tension T ). We obtain exact, analytical expressions ...

Local Equational Logic II

A logic may be called local if each model may be used to deene the truth. In the proposition calculus each boolean algebra deene the truth by its greatest element. In the equational logic the equality between the algebra elements deene the truth. In the clause Horn logic the truth is given by the interpretation of the predicats in the model. We give a categorial framework for these logics and w...

Parsing String Generating Hypergraph Grammars

A string generating hypergraph grammar is a hyperedge replacement grammar where the resulting language consists of string graphs i.e. hypergraphs modeling strings. With the help of these grammars, string languages like anbncn can be modeled that can not be generated by context-free grammars for strings. They are well suited to model discontinuous constituents in natural languages, i.e. constitu...