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TreeBased Picture Generation
 Theoretical Computer Science
, 2000
"... . The concept of treebased picture generation is introduced. It is shown that there are equivalent treebased definitions of four picturegenerating devices known from the literature, namely collage grammars, mutually recursive function systems, contextfree chaincode grammars, and 0Lsystems with ..."
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. The concept of treebased picture generation is introduced. It is shown that there are equivalent treebased definitions of four picturegenerating devices known from the literature, namely collage grammars, mutually recursive function systems, contextfree chaincode grammars, and 0Lsystems with turtle interpretation. Furthermore, generalisations of each of these systems are discussed. 1 Introduction During the last two decades picture generation has become a large field whose manyfold aspects are studied in mathematics as well as in practical and theoretical computer science. It attracts the interest of numerous researchers from diverse directions, which is no surprise because one can find in this area a great number of intellectually appealing mathematical and computational problems, interesting applications like the modelling of plant development and, one should not forget to mention this, an astonishing variety of beautiful pictures. In this paper picture generation is studied...
Grammatica: An Implementation of Algebraic Graph Transformation on Mathematica
"... . Grammatica is a prototype implementation of algebraic graph transformation based on relation algebra. It has been implemented using Mathematica on top of the Combinatorica package, and runs therefore on most platforms. It consists of Mathematica routines for representing, manipulating, display ..."
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. Grammatica is a prototype implementation of algebraic graph transformation based on relation algebra. It has been implemented using Mathematica on top of the Combinatorica package, and runs therefore on most platforms. It consists of Mathematica routines for representing, manipulating, displaying and transforming graphs, as well as routines implementing some relation algebratheoretic operations on graphs. It supports both interactive and automatic application of doublepushout graph productions, being therefore both a teaching aid and a research tool for algebraic graph transformation. 1 Introduction The methods and techniques of graph transformation have been under development for almost three decades now, although little e#orts have been devoted within the graph transformation community to issues of tool support. A few notable exceptions are the systems GraphEd [4], PROGRES [8], Agg [5], and Treebag [3]. Grammatica is a prototype implementation of doublepushout algebra...
The Complexity of the Exponential Output Size Problem for TopDown and BottomUp Tree Transducers
 Information and Computation
, 1999
"... . The exponential output size problem is to determine whether the size of output trees of a tree transducer grows exponentially in the size of input trees. In this paper the complexity of this problem is studied. It is shown to be NLcomplete for total topdown tree transducers, DEXPTIMEcomplet ..."
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. The exponential output size problem is to determine whether the size of output trees of a tree transducer grows exponentially in the size of input trees. In this paper the complexity of this problem is studied. It is shown to be NLcomplete for total topdown tree transducers, DEXPTIMEcomplete for general topdown tree transducers, and Pcomplete for bottomup tree transducers. 1 Introduction Topdown and bottomup tree transducers were introduced in the late sixties by Rounds and Thatcher [13, 16, 17, 18] as a generalisation of finitestate transducers on strings. The main motivation was to provide a simple formal model of syntaxdirected transformational grammars in mathematical linguistics and of syntaxdirected translation in compiler construction (for the latter, see the recent book by Fulop and Vogler [8]). Since that time it has turned out that tree transducers are a useful tool for many other areas, too, and their properties and extensions have been studied by a varie...
Picking Knots from Trees  The Syntactic Structure of Celtic Knotwork
 Proc. 1st Intl. Conference on Theory and Application of Diagrams 2000, volume 1889 of Lecture Notes in Arti cial Intelligence
, 2000
"... . Interlacing knotwork forms a signicant part of celtic art. From the perspective of computer science, it is a visual language following mathematically precise rules of construction. In this paper, we study the syntactic generation of celtic knots using collage grammars. Several syntactic regulat ..."
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. Interlacing knotwork forms a signicant part of celtic art. From the perspective of computer science, it is a visual language following mathematically precise rules of construction. In this paper, we study the syntactic generation of celtic knots using collage grammars. Several syntactic regulation mechanisms are employed in order to ensure that only consistent designs are generated. 1 Introduction A typical characteristic of visual languages is that the diagrams in such a language are related by a common structure and layout. In other words, the language is dened by a set of syntactic visual rules yielding the acceptable pictures. Formal picturegenerating methods help to understand the structure of the languages in question, to classify them, and to generate them automatically by means of computer programs. Fig. 1. A celtic knot Artists from many cultures have been using visual rules since ancient times in order to design diagrams of various sorts. Celtic diagrams, and in ...
Appligraph: Applications of Graph Transformation  Fourth Annual Progress Report
, 2001
"... This report summarizes the activities in the fourth year of the ESPRIT Working Group APPLIGRAPH, covering the period from April 1, 2000, to March 31, 2001. The principal objective of this Working Group is to promote applied graph transformation as a rulebased framework for the specication and devel ..."
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This report summarizes the activities in the fourth year of the ESPRIT Working Group APPLIGRAPH, covering the period from April 1, 2000, to March 31, 2001. The principal objective of this Working Group is to promote applied graph transformation as a rulebased framework for the specication and development of systems, languages, and tools and to improve the awareness of its industrial relevance
Prototyping the Tree Automata Workbench Marbles..................... 1
"... Abstract. In [Dre09], Drewes outlines Marbles, a programming framework for working in a generic and systematic way, not only on trees, as several frameworks already exist for this purpose, but on tree recognisers, transducers, generators and other formal devices as well. This thesis presents a proto ..."
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Abstract. In [Dre09], Drewes outlines Marbles, a programming framework for working in a generic and systematic way, not only on trees, as several frameworks already exist for this purpose, but on tree recognisers, transducers, generators and other formal devices as well. This thesis presents a prototype of a proposed implementation of this framework, demontrating its functionality by using it as a base for implementing a wellknown algorithm