7 Search Results for "Leijen, Daan"

Document
DOI: 10.4230/LIPIcs.CSL.2026.18
A Modular Framework for Proof-Search via Formalised Modal Completeness in HOL Light

Authors: Antonella Bilotta, Marco Maggesi, and Cosimo Perini Brogi

Published in: LIPIcs, Volume 363, 34th EACSL Annual Conference on Computer Science Logic (CSL 2026)

Abstract
We extend the existing HOL Light Library for Modal Systems (HOLMS) to support a modular implementation of modal reasoning within the HOL Light proof assistant. We deeply embed axiomatic calculi and relational semantics for seven normal modal logics (K, T, B, K4, S4, S5, GL) and formalise modal adequacy theorems for these systems. We then leverage those formalisations to implement a mechanism for automated reasoning via proof-search in the associated labelled sequent calculi, which we shallowly embed in HOL Light’s goal-stack mechanism. This way, we equip the general-purpose proof assistant with (semi)decision procedures for these logics that, in case of failure to construct a proof for the input formula, return a certified countermodel within the appropriate class for the logic under consideration. On the methodological side, we propose a precise measure of the modularity of our approach by systematically adopting Christopher Strachey’s distinction between ad hoc and parametric polymorphism throughout the library.
Cite as

Antonella Bilotta, Marco Maggesi, and Cosimo Perini Brogi. A Modular Framework for Proof-Search via Formalised Modal Completeness in HOL Light. In 34th EACSL Annual Conference on Computer Science Logic (CSL 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 363, pp. 18:1-18:29, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

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@InProceedings{bilotta_et_al:LIPIcs.CSL.2026.18,
  author =	{Bilotta, Antonella and Maggesi, Marco and Perini Brogi, Cosimo},
  title =	{{A Modular Framework for Proof-Search via Formalised Modal Completeness in HOL Light}},
  booktitle =	{34th EACSL Annual Conference on Computer Science Logic (CSL 2026)},
  pages =	{18:1--18:29},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-411-6},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{363},
  editor =	{Guerrini, Stefano and K\"{o}nig, Barbara},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2026.18},
  URN =		{urn:nbn:de:0030-drops-254427},
  doi =		{10.4230/LIPIcs.CSL.2026.18},
  annote =	{Keywords: Modal logic, HOL Light, Labelled sequent calculi, Logical verification, Interactive theorem proving, Automated proof-search}
}
Document
DOI: 10.4230/LIPIcs.WADS.2025.40
Grandchildren-Weight-Balanced Binary Search Trees

Authors: Vincent Jugé

Published in: LIPIcs, Volume 349, 19th International Symposium on Algorithms and Data Structures (WADS 2025)

Abstract
We revisit weight-balanced trees, also known as trees of bounded balance. Invented by Nievergelt and Reingold in 1972, these trees are obtained by assigning a weight to each node and requesting that the weight of each node should be quite larger than the weights of its children, the precise meaning of "quite larger" depending on a real-valued parameter γ. Blum and Mehlhorn then showed how to maintain them in a recursive (bottom-up) fashion when 2/11 ⩽ γ ⩽ 1-1/√2, their algorithm requiring only an amortised constant number of tree rebalancing operations per update (insertion or deletion). Later, in 1993, Lai and Wood proposed a top-down procedure for updating these trees when 2/11 ⩽ γ ⩽ 1/4. Our contribution is two-fold. First, we strengthen the requirements of Nievergelt and Reingold, by also requesting that each node should have a substantially larger weight than its grandchildren, thereby obtaining what we call grandchildren-balanced trees. Grandchildren-balanced trees are not harder to maintain than weight-balanced trees, but enjoy a smaller node depth, both in the worst case (with a 6 % decrease) and on average (with a 1.6 % decrease). In particular, unlike standard weight-balanced trees, all grandchildren-balanced trees with n nodes are of height less than 2 log₂(n). Second, we adapt the algorithm of Lai and Wood to all weight-balanced trees, i.e., to all parameter values γ such that 2/11 ⩽ γ ⩽ 1-1/√2. More precisely, we adapt it to all grandchildren-balanced trees for which 1/4 < γ ⩽ 1 - 1/√2. Finally, we show that, except in limit cases (where, for instance, γ = 1 - 1/√2), all these algorithms result in making a constant amortised number of tree rebalancing operations per tree update.
Cite as

Vincent Jugé. Grandchildren-Weight-Balanced Binary Search Trees. In 19th International Symposium on Algorithms and Data Structures (WADS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 349, pp. 40:1-40:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{juge:LIPIcs.WADS.2025.40,
  author =	{Jug\'{e}, Vincent},
  title =	{{Grandchildren-Weight-Balanced Binary Search Trees}},
  booktitle =	{19th International Symposium on Algorithms and Data Structures (WADS 2025)},
  pages =	{40:1--40:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-398-0},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{349},
  editor =	{Morin, Pat and Oh, Eunjin},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.WADS.2025.40},
  URN =		{urn:nbn:de:0030-drops-242710},
  doi =		{10.4230/LIPIcs.WADS.2025.40},
  annote =	{Keywords: Data structures, Balanced binary trees}
}
Document
DOI: 10.4230/LIPIcs.FSCD.2025.4
Substructural Parametricity

Authors: C. B. Aberlé, Karl Crary, Chris Martens, and Frank Pfenning

Published in: LIPIcs, Volume 337, 10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025)

Abstract
Ordered, linear, and other substructural type systems allow us to expose deep properties of programs at the syntactic level of types. In this paper, we develop a family of unary logical relations that allow us to prove consequences of parametricity for a range of substructural type systems. A key idea is to parameterize the relation by an algebra, which we exemplify with a monoid and commutative monoid to interpret ordered and linear type systems, respectively. We prove the fundamental theorem of logical relations and apply it to deduce extensional properties of inhabitants of certain types. Examples include demonstrating that the ordered types for list append and reversal are inhabited by exactly one function, as are types of some tree traversals. Similarly, the linear type of the identity function on lists is inhabited only by permutations of the input. Our most advanced example shows that the ordered type of the list fold function is inhabited only by the fold function.
Cite as

C. B. Aberlé, Karl Crary, Chris Martens, and Frank Pfenning. Substructural Parametricity. In 10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 337, pp. 4:1-4:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{aberle_et_al:LIPIcs.FSCD.2025.4,
  author =	{Aberl\'{e}, C. B. and Crary, Karl and Martens, Chris and Pfenning, Frank},
  title =	{{Substructural Parametricity}},
  booktitle =	{10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025)},
  pages =	{4:1--4:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-374-4},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{337},
  editor =	{Fern\'{a}ndez, Maribel},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2025.4},
  URN =		{urn:nbn:de:0030-drops-236193},
  doi =		{10.4230/LIPIcs.FSCD.2025.4},
  annote =	{Keywords: Substructural type systems, logical relations, ordered logic}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2025.4
Ensuring Convergence and Invariants Without Coordination

Authors: Dina Borrego, Nuno Preguiça, Elisa Gonzalez Boix, and Carla Ferreira

Published in: LIPIcs, Volume 333, 39th European Conference on Object-Oriented Programming (ECOOP 2025)

Abstract
The CAP theorem demonstrates a trade-off between consistency and availability (and, by extension, latency) in systems where network partitions are unavoidable, such as in cloud computing and local-first software. While adopting weak consistency can preserve availability, it may result in inconsistencies that compromise application correctness. Replicated data types provide a principled, coordination-free approach to guarantee convergence but do not consider application invariants. Existing methods for maintaining invariants in replicated systems either rely on coordination - undermining the benefits of weak consistency - or suffer from limited applicability. This paper introduces the No-Op framework, a generic approach for enforcing consistency without coordination while guaranteeing both convergence and invariant preservation. The core idea of the No-Op approach is to resolve conflicts among concurrent operations by prioritising one operation over the other according to programmer-defined conflict resolution policies. This prioritisation transforms the less-preferred operation into a no-side-effect operation, ensuring conflict-free execution. We formalise the model underlying the No-Op framework and introduce a replication protocol built upon it, accompanied by a formal proof of correctness for both the framework and the protocol. Furthermore, we demonstrate the framework’s applicability by showcasing the design of widely used replicated data types and the preservation of a wide range of application invariants.
Cite as

Dina Borrego, Nuno Preguiça, Elisa Gonzalez Boix, and Carla Ferreira. Ensuring Convergence and Invariants Without Coordination. In 39th European Conference on Object-Oriented Programming (ECOOP 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 333, pp. 4:1-4:29, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{borrego_et_al:LIPIcs.ECOOP.2025.4,
  author =	{Borrego, Dina and Pregui\c{c}a, Nuno and Gonzalez Boix, Elisa and Ferreira, Carla},
  title =	{{Ensuring Convergence and Invariants Without Coordination}},
  booktitle =	{39th European Conference on Object-Oriented Programming (ECOOP 2025)},
  pages =	{4:1--4:29},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-373-7},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{333},
  editor =	{Aldrich, Jonathan and Silva, Alexandra},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2025.4},
  URN =		{urn:nbn:de:0030-drops-232978},
  doi =		{10.4230/LIPIcs.ECOOP.2025.4},
  annote =	{Keywords: distributed systems, conflict resolution, RDTs, invariant preservation}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2025.9
Event Race Detection for Node.js Using Delay Injections

Authors: Andre Takeshi Endo and Anders Møller

Published in: LIPIcs, Volume 333, 39th European Conference on Object-Oriented Programming (ECOOP 2025)

Abstract
Node.js is a widely used platform for building JavaScript server-side web applications, desktop applications, and software engineering tools. Its asynchronous execution model is essential for performance, but also gives rise to event races, which cause many subtle bugs that can be hard to detect and reproduce. Current solutions to expose such races are based on modifications of the source code of the Node.js system or on guided executions using complex happens-before modeling. This paper presents a simpler and more effective approach called NACD that works by dynamically instrumenting core asynchronous operations in the Node.js runtime system to inject delays and thereby reveal event race bugs. It consists of a small, robust runtime instrumentation module implemented in JavaScript that is configured by a flexible JSON model of the essential parts of the Node.js API. Experimental results show that NACD can reproduce event race bugs with higher probability and fewer runs than state-of-the-art tools.
Cite as

Andre Takeshi Endo and Anders Møller. Event Race Detection for Node.js Using Delay Injections. In 39th European Conference on Object-Oriented Programming (ECOOP 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 333, pp. 9:1-9:28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{endo_et_al:LIPIcs.ECOOP.2025.9,
  author =	{Endo, Andre Takeshi and M{\o}ller, Anders},
  title =	{{Event Race Detection for Node.js  Using Delay Injections}},
  booktitle =	{39th European Conference on Object-Oriented Programming (ECOOP 2025)},
  pages =	{9:1--9:28},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-373-7},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{333},
  editor =	{Aldrich, Jonathan and Silva, Alexandra},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2025.9},
  URN =		{urn:nbn:de:0030-drops-233026},
  doi =		{10.4230/LIPIcs.ECOOP.2025.9},
  annote =	{Keywords: JavaScript, race conditions, flaky tests, event races, callback interleaving}
}
Document
DOI: 10.4230/DagRep.8.4.104
Algebraic Effect Handlers go Mainstream (Dagstuhl Seminar 18172)

Authors: Sivaramakrishnan Krishnamoorthy Chandrasekaran, Daan Leijen, Matija Pretnar, and Tom Schrijvers

Published in: Dagstuhl Reports, Volume 8, Issue 4 (2018)

Abstract
Languages like C\#, C++, or JavaScript support complex control flow statements like exception handling, iterators (yield), and even asynchrony (async/await) through special extensions. For exceptions, the runtime needs to be extended with exception handling stack frames. For iterators and asynchrony, the situation is more involved, as the compiler needs to turn regular code into stack restoring state machines. Furthermore, these features need to interact as expected, e.g. finally blocks must not be forgotten in the state machines for iterators. And all of this work needs to be done again for the next control flow abstraction that comes along. Or we can use algebraic effect handlers! This single mechanism generalizes all the control flow abstractions listed above and more, composes freely, has simple operational semantics, and can be efficiently compiled, since there is just one mechanism that needs to be supported well. Handlers allow programmers to keep the code in direct-style, which is easy to reason about, and empower library writers to implement various high-level abstractions without special extensions. The idea of algebraic effects handlers has already been experimented with in the form of small research languages and libraries in several mainstream languages, including OCaml, Haskell, Clojure, and Scala. The next step, and the aim of this seminar, is to seriously consider adoption by mainstream languages including both functional languages such as OCaml or Haskell, as well as languages like JavaScript and the JVM and .NET ecosystems.
Cite as

Sivaramakrishnan Krishnamoorthy Chandrasekaran, Daan Leijen, Matija Pretnar, and Tom Schrijvers. Algebraic Effect Handlers go Mainstream (Dagstuhl Seminar 18172). In Dagstuhl Reports, Volume 8, Issue 4, pp. 104-125, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)

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@Article{chandrasekaran_et_al:DagRep.8.4.104,
  author =	{Chandrasekaran, Sivaramakrishnan Krishnamoorthy and Leijen, Daan and Pretnar, Matija and Schrijvers, Tom},
  title =	{{Algebraic Effect Handlers go Mainstream (Dagstuhl Seminar 18172)}},
  pages =	{104--125},
  journal =	{Dagstuhl Reports},
  ISSN =	{2192-5283},
  year =	{2018},
  volume =	{8},
  number =	{4},
  editor =	{Chandrasekaran, Sivaramakrishnan Krishnamoorthy and Leijen, Daan and Pretnar, Matija and Schrijvers, Tom},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagRep.8.4.104},
  URN =		{urn:nbn:de:0030-drops-97623},
  doi =		{10.4230/DagRep.8.4.104},
  annote =	{Keywords: algebraic effect handlers, implementation techniques, programming abstractions, programming languages}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2015.568
Global Sequence Protocol: A Robust Abstraction for Replicated Shared State

Authors: Sebastian Burckhardt, Daan Leijen, Jonathan Protzenko, and Manuel Fähndrich

Published in: LIPIcs, Volume 37, 29th European Conference on Object-Oriented Programming (ECOOP 2015)

Abstract
In the age of cloud-connected mobile devices, users want responsive apps that read and write shared data everywhere, at all times, even if network connections are slow or unavailable. The solution is to replicate data and propagate updates asynchronously. Unfortunately, such mechanisms are notoriously difficult to understand, explain, and implement. To address these challenges, we present GSP (global sequence protocol), an operational model for replicated shared data. GSP is simple and abstract enough to serve as a mental reference model, and offers fine control over the asynchronous update propagation (update transactions, strong synchronization). It abstracts the data model and thus applies both to simple key-value stores, and complex structured data. We then show how to implement GSP robustly on a client-server architecture (masking silent client crashes, server crash-recovery failures, and arbitrary network failures) and efficiently (transmitting and storing minimal information by reducing update sequences).
Cite as

Sebastian Burckhardt, Daan Leijen, Jonathan Protzenko, and Manuel Fähndrich. Global Sequence Protocol: A Robust Abstraction for Replicated Shared State. In 29th European Conference on Object-Oriented Programming (ECOOP 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 37, pp. 568-590, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{burckhardt_et_al:LIPIcs.ECOOP.2015.568,
  author =	{Burckhardt, Sebastian and Leijen, Daan and Protzenko, Jonathan and F\"{a}hndrich, Manuel},
  title =	{{Global Sequence Protocol: A Robust Abstraction for Replicated Shared State}},
  booktitle =	{29th European Conference on Object-Oriented Programming (ECOOP 2015)},
  pages =	{568--590},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-86-6},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{37},
  editor =	{Boyland, John Tang},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2015.568},
  URN =		{urn:nbn:de:0030-drops-52385},
  doi =		{10.4230/LIPIcs.ECOOP.2015.568},
  annote =	{Keywords: distributed computing, eventual consistency, GSP protocol}
}
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