Borivoj Melichar

Learn More
We prove a property of generalized LR (GLR) parsing – if the grammar is without right and hidden left recursions, then the number of consecutive reductions between the shifts of two adjacent symbols cannot be greater than a constant. Further, we show that this property can be used for constructing an optimized version of our GLR parser. Compared with a(More)
The theory of formal string languages and of formal tree languages are both important parts of the theory of formal languages. Regular tree languages are recognized by finite tree automata. Trees in their postfix notation can be seen as strings. This paper presents a simple transformation from any given (bottom-up) finite tree automaton recognizing a(More)
Abs t r ac t . Approximate string matching is a sequential problem and therefore it is possible to solve it using finite automata. A nondeterministic finite automaton is constructed for string matching with k mismatches. It is shown, how "dynamic programming" and "shift-and" based algorithms simulate this nondeterministic finite automaton. The corresponding(More)
The subsequence matching problem is to decide, for given strings S and T , whether S is a subsequence of T . The string S is called the pattern and the string T the text. We consider the case of multiple texts and show how to solve the subsequence matching problem in time linear in the length of the pattern. For this purpose we build an automaton that(More)