Kayoko Shikishima-Tsuji

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The termination of a confluent one-rule string-rewriting system R = (s + I} is reduced to that of another one-rule system K = {s’ -B t’) such that s’ is self-overlap-free &of). A necessary and sufficient condition is given for termination of a one-rule system R = {s --+ t} such that s is sof and s overlaps r once on both sides.
Duplication is an operation generating a language from a single word by iterated application of rewriting rules u → uu on factors. We extend this operation to entire languages and investigate, whether the classes of the Chomsky hierarchy are closed under duplication. Here we treat mainly bounded duplication, where the factors duplicated cannot exceed a(More)
The hairpin completion is a formal operation inspired from DNA biochemistry. It is known that the (one step) hairpin completion of regular language is linear contextfree, but not regular in general. It is decidable whether the (one step) hairpin completion of regular language is regular. However, it is an open question whether the iterated hairpin(More)
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