A NOTE ON GRAMMARS WITH COORDINATES.

Abstract : Anderson has defined the notion of a 'graphical rewriting grammar', in which each production has an associated set of functions that compute coordinates for the symbols in the production's right member in terms of given coordinates of the symbols in its left member. It is shown that any such 'Anderson grammar' (AG) is equivalent to a 'one-dimensional' AG whose productions are all 'left-linear'; thus the power of an AG can be restricted only by restricting its coordinate-computing functions. On the other hand, even if the productions of an AG are left-linear and its functions are all computable by finite automata, its language need not be finite-state or even context-free. (Author)