10 research outputs found
The Way We Were: Structural Operational Semantics Research in Perspective
This position paper on the (meta-)theory of Structural Operational Semantic
(SOS) is motivated by the following two questions: (1) Is the (meta-)theory of
SOS dying out as a research field? (2) If so, is it possible to rejuvenate this
field with a redefined purpose?
In this article, we will consider possible answers to those questions by
first analysing the history of the EXPRESS/SOS workshops and the data
concerning the authors and the presentations featured in the editions of those
workshops as well as their subject matters.
The results of our quantitative and qualitative analyses all indicate a
diminishing interest in the theory of SOS as a field of research. Even though
`all good things must come to an end', we strive to finish this position paper
on an upbeat note by addressing our second motivating question with some
optimism. To this end, we use our personal reflections and an analysis of
recent trends in two of the flagship conferences in the field of Programming
Languages (namely POPL and PDLI) to draw some conclusions on possible future
directions that may rejuvenate research on the (meta-)theory of SOS. We hope
that our musings will entice members of the research community to breathe new
life into a field of research that has been kind to three of the authors of
this article.Comment: In Proceedings EXPRESS/SOS2023, arXiv:2309.0578
Pushdown Normal-Form Bisimulation: A Nominal Context-Free Approach to Program Equivalence
We propose Pushdown Normal Form (PDNF) Bisimulation to verify contextual
equivalence in higher-order functional programming languages with local state.
Similar to previous work on Normal Form (NF) bisimulation, PDNF Bisimulation is
sound and complete with respect to contextual equivalence. However, unlike
traditional NF Bisimulation, PDNF Bisimulation is also decidable for a class of
program terms that reach bounded configurations but can potentially have
unbounded call stacks and input an unbounded number of unknown functions from
their context. Our approach relies on the principle that, in model-checking for
reachability, pushdown systems can be simulated by finite-state automata
designed to accept their initial/final stack content. We embody this in a
stackless Labelled Transition System (LTS), together with an on-the-fly
saturation procedure for call stacks, upon which bisimulation is defined. To
enhance the effectiveness of our bisimulation, we develop up-to techniques and
confirm their soundness for PDNF Bisimulation. We develop a prototype
implementation of our technique which is able to verify equivalence in examples
from practice and the literature that were out of reach for previous work
Compositional Probabilistic Model Checking with String Diagrams of MDPs
We present a compositional model checking algorithm for Markov decision
processes, in which they are composed in the categorical graphical language of
string diagrams. The algorithm computes optimal expected rewards. Our
theoretical development of the algorithm is supported by category theory, while
what we call decomposition equalities for expected rewards act as a key
enabler. Experimental evaluation demonstrates its performance advantages.Comment: 32 pages, Extended version of a paper in CAV 202
Foundations of Software Science and Computation Structures
This open access book constitutes the proceedings of the 23rd International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The 31 regular papers presented in this volume were carefully reviewed and selected from 98 submissions. The papers cover topics such as categorical models and logics; language theory, automata, and games; modal, spatial, and temporal logics; type theory and proof theory; concurrency theory and process calculi; rewriting theory; semantics of programming languages; program analysis, correctness, transformation, and verification; logics of programming; software specification and refinement; models of concurrent, reactive, stochastic, distributed, hybrid, and mobile systems; emerging models of computation; logical aspects of computational complexity; models of software security; and logical foundations of data bases.
Foundations of Software Science and Computation Structures
This open access book constitutes the proceedings of the 24th International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2021, which was held during March 27 until April 1, 2021, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2021. The conference was planned to take place in Luxembourg and changed to an online format due to the COVID-19 pandemic. The 28 regular papers presented in this volume were carefully reviewed and selected from 88 submissions. They deal with research on theories and methods to support the analysis, integration, synthesis, transformation, and verification of programs and software systems
Foundations of Software Science and Computation Structures
This open access book constitutes the proceedings of the 23rd International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The 31 regular papers presented in this volume were carefully reviewed and selected from 98 submissions. The papers cover topics such as categorical models and logics; language theory, automata, and games; modal, spatial, and temporal logics; type theory and proof theory; concurrency theory and process calculi; rewriting theory; semantics of programming languages; program analysis, correctness, transformation, and verification; logics of programming; software specification and refinement; models of concurrent, reactive, stochastic, distributed, hybrid, and mobile systems; emerging models of computation; logical aspects of computational complexity; models of software security; and logical foundations of data bases.
Combinatorial Species and Labelled Structures
The theory of combinatorial species was developed in
the 1980s as part of the mathematical subfield of enumerative
combinatorics, unifying and putting on a firmer theoretical basis a
collection of techniques centered around generating
functions. The theory of algebraic data
types was developed, around the same time, in functional
programming languages such as Hope and Miranda, and is still used
today in languages such as Haskell, the ML family, and Scala. Despite
their disparate origins, the two theories have striking
similarities. In particular, both constitute algebraic frameworks in
which to construct structures of interest. Though the similarity has
not gone unnoticed, a link between combinatorial species and algebraic
data types has never been systematically explored. This dissertation
lays the theoretical groundwork for a precise—and, hopefully,
useful—bridge bewteen the two theories. One of the key
contributions is to port the theory of species from a classical,
untyped set theory to a constructive type theory. This porting process
is nontrivial, and involves fundamental issues related to equality and
finiteness; the recently developed homotopy type
theory is put to good use formalizing these issues in a
satisfactory way. In conjunction with this port, species as general
functor categories are considered, systematically analyzing the
categorical properties necessary to define each standard species
operation. Another key contribution is to clarify the role of species
as labelled shapes, not containing any data, and to
use the theory of analytic functors to model labelled
data structures, which have both labelled shapes and data associated
to the labels. Finally, some novel species variants are considered,
which may prove to be of use in explicitly modelling the memory layout
used to store labelled data structures
LIPIcs, Volume 261, ICALP 2023, Complete Volume
LIPIcs, Volume 261, ICALP 2023, Complete Volum