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We study decision problems of the form: given a regular or linear context-free language $L$, is there a word of a given fixed form in $L$, where given fixed forms are based on word operations copy, marked copy, shuffle and their…

Formal Languages and Automata Theory · Computer Science 2026-04-08 Vesa Halava , Tero Harju , Dirk Nowotka , Esa Sahla

The Turing machine models an old-fashioned computer, that does not interact with the user or with other computers, and only does batch processing. Therefore, we came up with a Reactive Turing Machine that does not have these shortcomings.…

Logic in Computer Science · Computer Science 2023-06-22 Jos C. M. Baeten , Cesare Carissimo , Bas Luttik

We study model checking algorithms for infinite families of finite-state labeled transition systems against temporal properties written in CTL*. Such families arise, for example, as models of highly configurable systems or software product…

Logic in Computer Science · Computer Science 2026-01-23 Roberto Pettinau , Christoph Matheja

We introduce a flexible class of well-quasi-orderings (WQOs) on words that generalizes the ordering of (not necessarily contiguous) subwords. Each such WQO induces a class of piecewise testable languages (PTLs) as Boolean combinations of…

Formal Languages and Automata Theory · Computer Science 2018-02-22 Georg Zetzsche

It is well-known that: (i) every context-free language over a singleton terminal alphabet is regular, and (ii) the class of languages that satisfy the Pumping Lemma is a proper super-class of the context-free languages. We show that any…

Formal Languages and Automata Theory · Computer Science 2018-07-13 Alberto Pettorossi , Maurizio Proietti

Cirquent calculus is a novel proof theory permitting component-sharing between logical expressions. Using it, the predecessor article "Elementary-base cirquent calculus I: Parallel and choice connectives" built the sound and complete…

Logic in Computer Science · Computer Science 2019-02-20 Giorgi Japaridze

Data-driven subword segmentation has become the default strategy for open-vocabulary machine translation and other NLP tasks, but may not be sufficiently generic for optimal learning of non-concatenative morphology. We design a test suite…

Computation and Language · Computer Science 2021-09-03 Chantal Amrhein , Rico Sennrich

In a jumping finite automaton, the input head can jump to an arbitrary position within the remaining input after reading and consuming a symbol. We characterize the corresponding class of languages in terms of special shuffle expressions…

Formal Languages and Automata Theory · Computer Science 2015-12-03 Henning Fernau , Meenakshi Paramasivan , Markus L. Schmid , Vojtěch Vorel

We define a new subclass of nondeterministic finite automata for prefix-closed languages called Flanked Finite Automata (FFA). We show that this class enjoys good complexity properties while preserving the succinctness of nondeterministic…

Formal Languages and Automata Theory · Computer Science 2015-09-23 Florent Avellaneda , Silvano Dal Zilio , Jean-Baptiste Raclet

Natural languages are believed to be (mildly) context-sensitive. Despite underpinning remarkably capable large language models, transformers are unable to model many context-free language tasks. In an attempt to address this limitation in…

Computation and Language · Computer Science 2024-05-15 Jiaoda Li , Jennifer C. White , Mrinmaya Sachan , Ryan Cotterell

Word puzzles and the problem of their representations in logic languages have received considerable attention in the last decade (Ponnuru et al. 2004; Shapiro 2011; Baral and Dzifcak 2012; Schwitter 2013). Of special interest is the problem…

Artificial Intelligence · Computer Science 2016-08-08 Tiantian Gao , Paul Fodor , Michael Kifer

We introduce a novel logic for the specification of context-free hyperproperties, which capture, e.g., the flow of information in security-critical recursive systems. Intuitively, the logic extends visibly pushdown automata by…

Logic in Computer Science · Computer Science 2026-05-07 Sarah Winter , Martin Zimmermann

This work proposes a simple training-free prompt-free approach to leverage large language models (LLMs) for the Chinese spelling correction (CSC) task, which is totally different from all previous CSC approaches. The key idea is to use an…

Computation and Language · Computer Science 2024-10-08 Houquan Zhou , Zhenghua Li , Bo Zhang , Chen Li , Shaopeng Lai , Ji Zhang , Fei Huang , Min Zhang

Recent work has demonstrated that pre-trained language models (PLMs) are zero-shot learners. However, most existing zero-shot methods involve heavy human engineering or complicated self-training pipelines, hindering their application to new…

Computation and Language · Computer Science 2022-11-24 Yu Fei , Ping Nie , Zhao Meng , Roger Wattenhofer , Mrinmaya Sachan

Improving the previously known best bound, we show that any recursively enumerable language can be generated with a non-returning parallel communicating (PC) grammar system having six context-free components. We also present a non-returning…

Formal Languages and Automata Theory · Computer Science 2009-07-30 Erzsébet Csuhaj-Varjú , György Vaszil

Probabilistic context-free grammars (PCFGs) are used to define distributions over strings, and are powerful modelling tools in a number of areas, including natural language processing, software engineering, model checking, bio-informatics,…

Formal Languages and Automata Theory · Computer Science 2014-07-08 Colin de la Higuera , James Scicluna , Mark-Jan Nederhof

This research introduces a new parsing approach, based on earlier syntactic work on context free grammar (CFG) and generalized phrase structure grammar (GPSG). The approach comprises both a new parsing algorithm and a set of syntactic rules…

Computation and Language · Computer Science 2026-02-17 Ghaly Hussein

Context-aware machine translation (MT) leverages document-level information, yet it does not consistently outperform sentence-level MT, as contextual signals are unevenly beneficial across sentences. Existing training objectives do not…

Computation and Language · Computer Science 2026-03-27 Ying Li , Xinglin Lyu , Junhui Li , Jinlong Yang , Hengchao Shang , Min Zhang , Shimin Tao , Daimeng Wei

Textless spoken language models (SLMs) are generative models of speech that do not rely on text supervision. Most textless SLMs learn to predict the next semantic token, a discrete representation of linguistic content, and rely on a…

Computation and Language · Computer Science 2025-10-23 Ju-Chieh Chou , Jiawei Zhou , Karen Livescu

Cross-lingual Text Classification (CLC) consists of automatically classifying, according to a common set C of classes, documents each written in one of a set of languages L, and doing so more accurately than when naively classifying each…

Machine Learning · Computer Science 2021-09-22 Andrea Esuli , Alejandro Moreo , Fabrizio Sebastiani