Structural Descriptions, Transformational Rules, and Pattern Analysis.
William E Underwood, Laveen N. Kanal · 1973
Abstract : In the paper two equivalent notations are defined for describing the structure assigned to graph-like patterns by web grammar derivations. The notion of a transformational rule for webs is defined and the use of transformational rules for describing structural relations among webs that cannot be indicated by context-free web grammars is illustrated. (Author)