Table Of ContentLecture Not ens i
Computer Science
Edited by G. Goos and .J Hartmanis
17
IIIIIIIII IIIIII II III I II I I I I III I I I
,atamotuA
segaugnaL dna gnimmargorP
Colloquium, Sixth Graz, July Austria, 16-20, 1979
Edited yb Hermann .A Maurer
I IIII IIII I II II I
galreV-regnirpS
nilreB Heidelberg kroYweN 1979
Editorial Board
P. Brinch Hansen D. Gries C. Moler G. Seegm~iller
.J Stoer N. Wirth
Editor
Hermann A. Maurer
Institut f0r Informations-
verarbeitung
Technische Universit~it Graz
Steyrergasse 17
8010 Graz/Austria
AMS (1970): Subject Classifications 68-XX
CR Subject (1974): 4.1, Classifications 4.2, 5.2, 5.3
tSBN 3-540-09510-1 Berlin Heidelberg Springer-Verlag New York
ISBN 0-387-09510-1 Springer-Verlag New York Heidelberg Berlin
Library of Congress Cataloging in Publication Data.
Colloquium on Automata, Languages and programming, 6th, Graz, 1979. Automata,
languages and programming.( Lecture notes in computer science ; )17 Includes index.
.1 Sequential machinteh eory--Congresses. 2. Formal languages--Congresses,
3. Programming languages (Electronic computers)--Congresses. .I Maurer,
Hermann 1941- A., .II Title. LlI Series.
QA267.5S4C63 1979 001.6'42 ?~-15859
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@ by Springer-Verlag Berlin Heidelberg 1979
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ECAFERP
ehT Sixth Colloquium no Automata, segaugnaL dna gnimmargorP (ICALP )97 saw dedecerp
by similar colloquia in Paris (1972), SaarbrUcken (1974), Edinburgh (1976), Turku
(1977) dna Udine (1978), all sponsored by SCTAE (European Association for Theoretical
retupmoC Science).
Of a total of 931 papers submitted to PLACI 79, fifty papers were selected. Together
with three invited presentations they are contained in this volume.
ehT program committee of PLACI 97 consisted of G.Ausiello, W.Brauer, K.Culik II, J.
ed Bakker, E.Engeler, S.Even, M.Harrison, l.M.Havel, J.Hopcroft, G.Hotz, W.Kuich,
H.Maurer (chairman), M.Nivat, M.Paterson, Z.Pawlak, A.Salomaa, ,dooW.D H.Zima.
sA conference chairman, I would like to thank the srebmem of the program committee
for their hard work in evaluating the submitted papers. Special thanks are also eud
to the following referees ohw helped in the refereeing process: A.Aho, J.Albert, .G
Andrews, K.R.Apt, J.Archer, E.A.Ashcroft, L.Banachowski, G.Baron, C.Batini, J.C.Beatty,
J.Becvar, D.Bini, A.Blikle, ,mh~B.C R.Book, S,Breidbart, .A ed Bruin, J.Brzozowski,
R.Cartwright, L.M.Chirica, R.S.Cohen, A.B.Cremers, P.Dembinski, K.Ecker, H.Ehrig, .M
Furst, G.Gati, G.Goos, J.Gorski, M.Grabowski, D.Gries, J.Gruska, J.Grzymala-Busse, .V
Haase, M.Hofri, M.Jazayeri, J.Karhum~ki, O.Kariv, M.Karpinski, C.Keleman, B.Konilcowska,
A.Krecmar, H.P.Kriegel, F.Krieger, M.Lao, R.Leip~l~, M.Linna, F.Luk, G.Mahr, T.S.E.
,muabiaM J.Maluszynski, A.Marchetti-Spaccamela, A.Mazurkiewicz, L.G.L.T.Meertens, .R
Milner, A.Moura, T.MUldner, K.MUIIer, E.J.Neuhold, A.Ob~tulowicz, J.Opatrny, Th.Ott-
,nnam D.M.R.Park, A.Paz, M.Penttonen, A.Pettorossi, F.PIAsil, H.Prodinger, V.Rajlich,
P.Raulefs, J.C.Reynolds, J.L.Richier, ,hedoR.M edLP.W Roever,'F.Romani, D.Rotem, .P
Ruzicka, A.Salwicki, G.Schlageter, F.Schneider, E.Shamir, J.Simon, M.Steinby, W.Stucky,
S.Termini, J.W.Thatcher, F.J.Urbanek, V.K.Vaishnavi, P.van edmE Boas, J.van ,newueeL
J.Weglarz, L.Wegner, K.Weihrauch, J.Winkowski, C.K.Yap.
Finally, the support of the Austrian Federal Ministry for Science dna Research, the
Province of Styria, the City of Graz, the Center Research Graz, MBI Austria, Sperry
Univac, the Institut f. etdnawegnA Informatik dnu Formale Beschreibungsverfahren -
Universit~t Karlsruhe dna the Technical University of Graz is gratefully .degdelwonkca
Last not least, I want to thank the srebmem of the organizing committee dna ym secre-
tary Mrs. A.Kleinschuster for their help in organizing the conference, dna Springer-
Verlag for excellent cooperation concerning the publication of this volume.
Graz, April 9791
nnamreH Maurer
STNETNOC
E.Astesiano and G.Costa
Sharing in nondeterminism . . . . . . . . . . . . . . . . .
J.Berstel
Sur les mots sans carr~ d~finis par un morphisme . . . . . . . . . 61
A.Bertoni, G.Mauri and P.A.Miglioli
A characterization of abstract data as model-theoretic invariants 26
M.Blattner
Inherent ambiguities in families of grammars . . . . . . . . . . 38
R.V.Book and F.-J.Brandenburg
Representing complexity classes by equality sets . . . . . . . . . 49
B.v.BraunmUhl and E.Hotzel
Supercounter machines . . . . . . . . . . . . . . . . . . 58
M.Broy, W.Dosch, H.Partsch, P.Pepper and M.Wirsing
Existential quantifiers in abstract data types . . . . . . . . . . 37
C.Choffrut
A generalization of Ginsburg and Rose's
characterization of G-S-H mappings . . . . . . . . . . . . . . 88
L.Chottin
Strict deterministic languages and controlled rewriting systems . . . . 401
B.Commentz-Walter
A string matching algorithm fast on the average . . . . . . . . . 118
M.Coppo, M.Dezani-Ciancaglini and .P Salle'
Functional characterization of some
semantic equalities inside ~-calculus . . . . . . . . . . . . . 133
Vl
A.B.Cremers and T.N.Hibbard
Arbitration and queueing under limited shared storage requirements . . . . 741
K.Culik II
nO the homomorphic characterizations of families of languages . . . . . . 161
P.Dembihski and J.Ma~uszyhski
owT level grammars: CF-grammars with equation schemes . . . . . . . . . 171
N.Dershowitz and Z.Manna
Proving termination with multiset orderings . . . . . . . . . . . . 188
P.Deussen
enO abstract accepting algorithm for all kinds of parsers . . . . . . . . 203
A.G.Duncan and L.Yelowitz
Studies in abstract/concrete mappings in proving algorithm correctness 218
F.E.Fich and J.A.Brzozowski
A characterization of a dot-depth two analogue of
generalized definite languages . . . . . . . . . . . . . . . . 230
D.Friede
Partitioned LL(k) grammars . . . . . . . . . . . . . . . . . . 245
J.H.Gallier
Recursion schemes and generalized interpretations . . . . . . . . . . 256
J.Goldstine
A rational theory of AFLs . . . . . . . . . . . . . . . . . . 271
J.Hartmanis
nO the succinctness of different representations of languages . . . . . . 282
S.Istrail
A fixed-point theorem for recursive-enumerable languages and
some considerations about fixed-point semantics of monadic programs . . . . 289
IIV
oknaJ.W
Hierarchic index sequential search with optimal variable block
size dna its minimal expected rebmun of comparisions . . . . . . . . . 403
dnornaeJ.J,H
A unique termination theorem for a theory with
generalised commutative axioms . . . . . . . . . . . . . . . . 613
arumimaK.T dna G.Slutzki
Dags and Chomsky hierarchy . . . . . . . . . . . . . . . . . 331
R.Karp
Recent advances in the probabilistic analysis of
graph-theoretic algorithms (Invited address) . . . . . . . . . . . 338
pmeK.R
nO the average stack size of regularly distributed binary trees . . . . . 340
W.Kowalk and R.Valk
nO reductions of parallel programs . . . . . . . . . . . . . . . 356
W.Kuich, H.Prodinger and F.J.Urbanek
nO the height of derivation trees . . . . . . . . . . . . . . . 370
Z.Manna and A.Pnueli
The modal logic of programs (Invited address) . . . . . . . . . . . 385
F.Meyer auf der Heide
A comparision between two variations of a pebble game on graphs . . . . . 411
D.R.Milton and C.N.Fischer
LL(k) parsing for attributed grammars . . . . . . . . . . . . . . 422
B.Monien and l.H.Sudborough
nO eliminating nondeterminism from Turing machines
which use less than logarithm worktape space . . . . . . . . . . . 431
VIII
A.Nijholt
Structure preserving transformations no non-left-recursive grammars . . . . 644
C.H.Papadimitriou dna M.Yannakakis
ehT complexity of restricted muminim spanning tree problems . . . . . . . 064
grebnezoR.G
A systematic approach to formal language theory
through parallel rewriting (Invited address) . . . . . . . . . . . . 174
grebnezoR.G dna D.Vermeir
Extending the notion of finite index . . . . . . . . . . . . . . 974
ozzuR.L.W
nO the complexity of general context-free language
parsing dna recognition . . . . . . . . . . . . . . . . . . 984
J.E.Savage dna ymawS.S
Space-time tradeoffs for oblivious integer multiplication . . . . . . . 894
tdimhcS.G
Investigating programs in terms of partial graphs . . . . . . . . . . 505
egahn~hcS.A
nO the power of modnar access machines . . . . . . . . . . . . . 025
R.L.Schwartz
nA axiomatic treatment of LOGLA 86 routines . . . . . . . . . . . . 035
namleS.L.A
P-selective sets, tally languages, dna the behavior
of polynomial time reducibilities no PN . . . . . . . . . . . . . 645
R.Sethi dna gnaT,A
Constructing call-by-value continuation semantics . . . . . . . . . . 655
sdleihS.W.M dna P,E.Lauer
A formal semantics for concurrent systems . . . . . . . . . . . . . 175
XJ
S.Sippu and E.Soisalon-Soln,..en
nO constructing LL(k) parsers . . . . . . . . . . . . . . . . . 585
J.W.Thatcher. E.G.Wagner and J.B.Wright
More on advice on structuring compilers and proving them correct . . . . . 695
D.Th~rien
Languages of nilpotent and solvable groups . . . . . . . . . . . . 616
J .Tiuryn
Unique fixed points vs. least fixed points . . . . . . . . . . . . 633
E, Ukkonen
A modification of the LR(k) method for constructing
compact bottom-up parsers . . . . . . . . . . . . . . . . . . 646
k,Ury
Optimal decomposition of linear automata . . . . . . . . . . . . . 659
.Wegner L
Bracketed two-level grammars - a decidable and
practical approach to language definitions . . . . . . . . . . . . 668
Index of authors . . . . . . . . . . . . . . . . . . . 683
SHARING IN NONDETERMINISM
Egidio ASTESIANO - Gerardo COSTA
Istituto di Matematica dell'Universitg di Genova
Via L.B.Alberti, 4 - 16132 Genova - Italy
ABSTRACT. We consider a language of typed ~-expressions with primitives including
nondeterministic choice operators. Starting from the natural idea that a ~irst order
nondeterministic procedure should define a one-many function, we give a reduction
system in which ground arguments are shared, in order to avoid some unnatural conse-
quences due to unrestricted application of the copy-rule. This is achieved by extending
the language and modifying the usual ~-rule. Then we discuss how to define a correspo~
ding denotational semantics, establishing in particular the existence of a model which
is fully abstract w.r.t, the operational semantics.
.] INTRODUCTION
Consider the usual language of first order deterministic recursive vrocedures,
enriched with a binary choice operator or and extend the usual evaluation mechanism by
letting t or 't evaluate to either t or 't . Then consider the following exam-
ple /HA1/ ~ where x ranges over the domain of non-negative integers ~ :
F(x) ~= if x=O then O else G(x or x-l)
G(x) #= if x=O then O else if x=l then I else 2
Evaluation of F(1), using an outermost strategy, yields, as possible values, O, I and
2. Hennessy and Ashcroft point out that in a functional model corresponding to this
evaluation strategy F and G cannot denote functions f and g from ~ into ~ . 2 Indeed
we would have: f(1) = g({O,l}) = g(O) U g(1) = {O,I} , in contrast with the operational
result. This motivates in /HAI,HA2/ the choice of a model in which the meanings for F
and G are functions from ~ \ 2 {@} into itself. From a mathematical point of view, how-
ever, it seems perfectly reasonable to take a different apvroaeh: the equation for G
is deterministic and by itself defines a function from ~ into ~ , it should then defi-
ne the "same" (see below) function when considered together with the equation for F.
In general, it is mathematically sound to say that nondeterministic recursive proce-
dures define one-many functions. In this framework, deterministic procedures, like the
one for G, define one-singleton functions and the result of a~plying a function f to
a set A is given by U {f(a), @ a A} . This is the approach we shall take here (the
same choice is made in /ANI,A~N2/, though in a different setting).
Looking for an operational semantics corresponding to this (intuitive) model, we
remark that the point in the above example is that G makes two copies of its argument,
