Location






The seminar is held in hybrid format, in person (Múzeum krt. 4/i Room 224) and online at the following link:

https://us02web.zoom.us/j/84594385686?pwd=a7KPWoNLrPg11xNTi5Ug91YR5mHmmS.1
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6 March (Friday) 4:15 PM  Room 224 + ONLINE 
Mátyás Lagos
Department of Logic, Institute of Philosophy,
Eötvös Loránd University, Budapest
 
Generalization via Aggregation: An Analogical Inference Mechanism for Natural Language Syntax
How do speakers of a language infer the grammatical structure of a newly heard sentence? In exemplar-based theories of language, this inference process is said to consist of comparing the novel sentence to sentences that the speaker has already heard, and making analogical generalizations from the observed partial similarities. There have been attempts at fully specifying and computationally implementing such a process, but it remains an open question whether this is a feasible approach, given the fact that even relatively short word sequences tend to occur very infrequently in corpora. In this talk, I propose a novel exemplar-based grammatical inference mechanism and present some experiments testing its feasibility.



13 March (Friday) 4:15 PM  Room 224 + ONLINE 
Hongkai Yin
Central European University, Vienna
 
The Guarded Fluted Fragment of First-Order Logic
The guarded fluted fragment is the intersection of the guarded fragment and the fluted fragment of first-order logic. In this talk I showcase a model construction technique which turns each first-order structure into a modal structure and back. Based on that, I introduce a translation of the guarded fluted fragment to the basic modal logic extended with the universal modality, providing a simulation of the fragment as well as a new proof of the ExpTime-completeness of the satisfiability problem. Moreover, the technique induces a variant of the unraveling construction. As an application of the unraveling, I show that the analog of the Łoś-Tarski Preservation Theorem holds in the fragment.



20 March (Friday) 4:15 PM  Room 224 + ONLINE 
Tibor Papp
Eötvös Loránd University, Department of Logic
 
Introduction to Universal Logic
The first part of my doctoral thesis is a self-developed metalogical theory, called Universal Logic (UL). The doctoral thesis outlines UL as follows:

There is a hidden internal architecture of logic that is obscured by the implicit paradigms governing syntax, semantics, and consequence. By explicating and reformulating these paradigms in two distinct directions, this hidden architecture becomes visible.

First, modern (post-Fregean) logic has typically approached traditional (pre-Fregean) logic by reformulating its categories within modern logical frameworks. To make the internal architecture of logic visible, however, this direction must be reversed: modern logic must be reconstructed on the basis of the categorical distinctions already present in traditional logic.

Second, the internal architecture of logic has typically been sought through its algebraisation. Yet algebraic abstraction, while structurally powerful, necessarily suppresses certain features specific to logical construction, and therefore cannot render the full internal architecture of logic visible. To make this architecture fully explicit, it is not logic that must be algebraised, but algebra that must be logified.

As a result of this reformulation, the completeness theorem emerges in a new light. It is a universal property of the internal architecture of logic itself, rather than a result tied to particular logical calculi, and it can be formally proved within the new paradigms that make this architecture explicit. In other words, the absence of a completeness theorem in higher-order logics does not reflect an intrinsic limitation of logic itself; it reveals instead that the implicit paradigms governing syntax, semantics, and consequence are insufficient to support completeness in higher orders.

Of course, I cannot present the entire UL during the seminar lecture, as it is a mathematical construction of over 100 pages. The aim of the lecture is to show the basic ideas on which UL is based.

Finally, an important note: I will give the lecture in Hungarian.



27 March (Friday) 4:15 PM  Room 224 + ONLINE 
Domonkos Inges
Eötvös Loránd University, Department of Logic
 
About the distinguishing of S(Kn) and the usage of distinguishing coloring in cryptographic protocols
In this thesis, we consider a way of breaking a graph's symmetry: distinguishing colorings. A distinguishing coloring c of G colors the vertices of G so that the only automorphism of the colored graph (G,c) is the identity map. The distinguishing number of G, D(G), is the minimum number of colors needed to create a distinguishing coloring of G. The cost number of Gρ(G), is the size of the minimum color class of an optimal distinguishing coloring of G.

We provide the following result for the complete graph and its subdivision graph: ρ(S(Kn))=ρ'(Kn), where ρ'(G) is the cost number of a distinguishing edge coloring of G.

Furthermore, we present the known complexity of the language DIST = {(G,k) : D(G) ≤ k}. We explore a research area by giving a sketch of a zero-knowledge protocol for someone to commit to a distinguishing coloring on a graph.