Anzeige
Erschienen in:
2011 | OriginalPaper | Buchkapitel
A Fragment of ML Decidable by Visibly Pushdown Automata
verfasst von : David Hopkins, Andrzej S. Murawski, C. -H. Luke Ong
Erschienen in: Automata, Languages and Programming
Verlag: Springer Berlin Heidelberg
Aktivieren Sie unsere intelligente Suche, um passende Fachinhalte oder Patente zu finden.
Wählen Sie Textabschnitte aus um mit Künstlicher Intelligenz passenden Patente zu finden. powered by
Markieren Sie Textabschnitte, um KI-gestützt weitere passende Inhalte zu finden. powered by
The simply-typed, call-by-value language,
RML
, may be viewed as a canonical restriction of Standard ML to ground-type references, augmented by a “bad variable” construct in the sense of Reynolds. By a
short
type, we mean a type of order at most 2 and arity at most 1. We consider the
O-strict
fragment of (finitary)
RML
,
RML
O
−
Str
, consisting of terms-in-context
x
1
:
θ
1
, ... ,
x
n
:
θ
n
⊢
M
:
θ
such that
θ
is short, and every argument type of every
θ
i
is short.
RML
O
−
Str
is surprisingly expressive; it includes several instances of (in)equivalence in the literature that are challenging to prove using methods based on (state-based) logical relations. We show that it is decidable whether a given pair of
RML
O
−
Str
terms-in-context is observationally equivalent. Using the fully abstract game semantics of
RML
, our algorithm reduces the problem to the language equivalence of visibly pushdown automata. When restricted to terms in canonical form, the problem is EXPTIME-complete.