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Grammars with Restricted Derivation Trees
Koutný, Jiří ; Janoušek, Jan (oponent) ; Vojnar, Tomáš (oponent) ; Meduna, Alexandr (vedoucí práce)
This doctoral thesis studies theoretical properties of grammars with restricted derivation trees. After presenting the state of the art concerning this investigation area, the research is focused on the three main kinds of the restrictions placed upon the derivation trees. First, it introduces completely new investigation area represented by cut-based restriction and examines the generative power of the grammars restricted in this way. Second, it investigates several new properties of path-based restriction placed upon the derivation trees. Specifically, it studies the impact of erasing productions on the generative power of grammars with restricted path and introduces two corresponding normal forms. Then, it describes a new relation between grammars with restricted path and some pseudoknots. Next, it presents a counterargument to the generative power of grammars with controlled path that has been considered as well-known so far. Finally, it introduces a generalization of path-based restriction to not just one but several paths. The model generalized in this way is studied, namely its pumping, closure, and parsing properties.
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Formal Models of Distributed Computation
Soukup, Ondřej ; Horváth,, Géza (oponent) ; Rogalewicz, Adam (oponent) ; Meduna, Alexandr (vedoucí práce)
The present thesis introduces derivation trees for several different types of grammars in generalized Kuroda normal forms; namely, general, regular-controlled, and scattered context grammars and cooperating distributed grammar systems. It defines simple tree-based properties related to non-context-free properties of all grammars in question and shows that if there exists a limiting constant k such that every sentence in the generated language L is the frontier of a derivation tree in which the number of occurrences of the defined tree-based properties is limited by k, the language L is in fact context-free. The thesis explains that this result represents a powerful tool for showing languages to be context-free. It also provides illustrations and examples which sketch how to apply this tool in practice.
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Formal Models of Distributed Computation
Soukup, Ondřej ; Horváth,, Géza (oponent) ; Rogalewicz, Adam (oponent) ; Meduna, Alexandr (vedoucí práce)
The present thesis introduces derivation trees for several different types of grammars in generalized Kuroda normal forms; namely, general, regular-controlled, and scattered context grammars and cooperating distributed grammar systems. It defines simple tree-based properties related to non-context-free properties of all grammars in question and shows that if there exists a limiting constant k such that every sentence in the generated language L is the frontier of a derivation tree in which the number of occurrences of the defined tree-based properties is limited by k, the language L is in fact context-free. The thesis explains that this result represents a powerful tool for showing languages to be context-free. It also provides illustrations and examples which sketch how to apply this tool in practice.
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Grammars with Restricted Derivation Trees
Koutný, Jiří ; Janoušek, Jan (oponent) ; Vojnar, Tomáš (oponent) ; Meduna, Alexandr (vedoucí práce)
This doctoral thesis studies theoretical properties of grammars with restricted derivation trees. After presenting the state of the art concerning this investigation area, the research is focused on the three main kinds of the restrictions placed upon the derivation trees. First, it introduces completely new investigation area represented by cut-based restriction and examines the generative power of the grammars restricted in this way. Second, it investigates several new properties of path-based restriction placed upon the derivation trees. Specifically, it studies the impact of erasing productions on the generative power of grammars with restricted path and introduces two corresponding normal forms. Then, it describes a new relation between grammars with restricted path and some pseudoknots. Next, it presents a counterargument to the generative power of grammars with controlled path that has been considered as well-known so far. Finally, it introduces a generalization of path-based restriction to not just one but several paths. The model generalized in this way is studied, namely its pumping, closure, and parsing properties.
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