Results 1 
6 of
6
Operational domain theory and topology of a sequential language
 In Proceedings of the 20th Annual IEEE Symposium on Logic In Computer Science
, 2005
"... A number of authors have exported domaintheoretic techniques from denotational semantics to the operational study of contextual equivalence and order. We further develop this, and, moreover, we additionally export topological techniques. In particular, we work with an operational notion of compact ..."
Abstract

Cited by 11 (6 self)
 Add to MetaCart
A number of authors have exported domaintheoretic techniques from denotational semantics to the operational study of contextual equivalence and order. We further develop this, and, moreover, we additionally export topological techniques. In particular, we work with an operational notion of compact set and show that total programs with values on certain types are uniformly continuous on compact sets of total elements. We apply this and other conclusions to prove the correctness of nontrivial programs that manipulate infinite data. What is interesting is that the development applies to sequential programming languages, in addition to languages with parallel features. 1
A metric model of PCF
, 1998
"... We introduce a computationally adequate metric model of PCF, based on the fact that the category of nonexpansive maps of complete bounded ultrametric spaces is cartesian closed. The model captures certain temporal aspects of highertype computation and contains both extensional and intensional func ..."
Abstract

Cited by 6 (0 self)
 Add to MetaCart
We introduce a computationally adequate metric model of PCF, based on the fact that the category of nonexpansive maps of complete bounded ultrametric spaces is cartesian closed. The model captures certain temporal aspects of highertype computation and contains both extensional and intensional functions. We show that Scott’s model arises as its extensional collapse. The intensional aspects of the metric model are illustrated via a Gödelnumberfree version of Kleene’s Tpredicate.
Effective and sequential definition by cases on the reals via infinite signeddigit numerals
 In Third Workshop on Computation and Approximation (Comprox III), volume 13 of Electronic Notes in Theoretical Computer Science
, 1998
"... The lexicographical and numerical orders on infinite signeddigit numerals are unrelated. However, we show that there is a computable normalization operation on pairs of signeddigit numerals such that for normal pairs the two orderings coincide. In particular, one can always assume without loss of ..."
Abstract

Cited by 2 (1 self)
 Add to MetaCart
The lexicographical and numerical orders on infinite signeddigit numerals are unrelated. However, we show that there is a computable normalization operation on pairs of signeddigit numerals such that for normal pairs the two orderings coincide. In particular, one can always assume without loss of generality that any two numerals that denote the same number are themselves the same. We apply the ordernormalization operator to easily obtain an effective and sequential definitionbycases scheme in which the cases consist of inequalities between real numbers. Key words: Real number computation, parallel conditional. 1
Lenient evaluation is neither strict nor lazy
, 2000
"... What is a nonstrict functional language? Is a nonstrict language necessarily lazy? What additional expressiveness brings nonstrictness, with or without laziness? This paper tries to shed some light on these questions. First, in order to characterize nonstrictness, different evaluation strategies ..."
Abstract
 Add to MetaCart
What is a nonstrict functional language? Is a nonstrict language necessarily lazy? What additional expressiveness brings nonstrictness, with or without laziness? This paper tries to shed some light on these questions. First, in order to characterize nonstrictness, different evaluation strategies are introduced: strict, lazy, and lenient. Then, using program examples, how these evaluation strategies differ from each other is examined, showing that nonstrictness, even without laziness, allows a more general use of recursive definitions. We also report on a small experiment that we performed to examine how, in practice, laziness was used in a number
in a highertype setting
"... We show that, in a fairly general setting including highertypes, may, must and probabilistic testing are semidecidable. The case of must testing is perhaps surprising, as its mathematical definition involves universal quantification over the infinity of possible outcomes of a nondeterministic prog ..."
Abstract
 Add to MetaCart
We show that, in a fairly general setting including highertypes, may, must and probabilistic testing are semidecidable. The case of must testing is perhaps surprising, as its mathematical definition involves universal quantification over the infinity of possible outcomes of a nondeterministic program. The other two involve existential quantification and integration. We also perform first steps towards the semidecidability of similar tests under the simultaneous presence of nondeterministic and probabilistic choice. Keywords: Nondeterministic and probabilistic computation, highertype computability theory and exhaustible sets, may and must testing, operational and denotational semantics, powerdomains. 1