JUCS - Journal of Universal Computer Science 8(2): 141-152, doi: 10.3217/jucs-008-02-0141
Additive Distances and Quasi_Distances Between Words
expand article infoCristian S. S. Calude‡, Kai Salomaa§, Sheng Yu|
‡ University of Auckland, Auckland, New Zealand§ Queen's University, Kingston, Canada| Department of Computer Science, University of Western Ontario London, Canada

Corresponding author: Cristian S. Calude ( cristian@cs.auckland.ac.nz )

© Cristian S. Calude, Kai Salomaa, Sheng Yu.
This article is freely available under the J.UCS Open Content License.
Citation: Calude CSS, Salomaa K, Yu S (2002) Additive Distances and Quasi_Distances Between Words. JUCS - Journal of Universal Computer Science 8(2): 141-152. https://doi.org/10.3217/jucs-008-02-0141
Open Access
Abstract
We study additive distances and quasi-distances between words. We show that every additive distance is finite. We then prove that every additive quasi-distance is regularity-preserving, that is, the neighborhood of any radius of a regular language with respect to an additive quasi-distance is regular. Finally, similar results will be proven for context-free, computable and computably enumerable languages. 1.) C. S. Calude, K. Salomaa, S. Yu (eds.). Advances and Trends in Automata and Formal Languages. A Collection of Papers in Honour of the 60th Birthday of Helmut Jürgensen.
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