Summary: Effective Lossy Queue Languages
Parosh Aziz Abdulla 1 , Luc Boasson 2 , and Ahmed Bouajjani 2 ?
1 DoCS, Uppsala University, P.O. Box 325, S­75105 Uppsala, Sweden.
parosh@docs.uu.se
Phone: (+46) 18 471 31 63. Fax: (+46) 18 55 02 25.
2
Liafa, Univ. of Paris 7, Case 7014, 2 place Jussieu, F­75251 Paris Cedex 05, France.
flub,aboug@liafa.jussieu.fr
Phone: (+33) 1 4427 2841/7819. Fax: (+33) 1 4427 6849.
ICALP'01 submission, TRACK B
Abstract. Although the set of reachable states of a lossy channel system (LCS)
is regular, it is well­known that this set cannot be constructed effectively. In this
paper, we characterize significant classes of LCS for which the set of reachable
states can be computed. Furthermore, we show that, for slight generatlizations
of these classes, computability can no longer be achieved.
To carry out our study, we define rewriting systems which capture the behaviour
of LCS, in the sense that (i) they have a FIFO­like semantics and (ii) their lan­
guages are downward closed with respect to the substring relation. The main
result of the paper shows that, for context­free rewriting systems, the corre­
sponding language can be computed. An interesting consequence of our results

Source: Abdulla, Parosh Aziz - Department of Information Technology, Uppsala Universitet

Collections: Computer Technologies and Information Sciences