arXiv subjects

Aleksandar Pavlović

Publications and source records attributed to Aleksandar Pavlović.

9 recordsLinked to original sources

arXiv2026

BoxLitE: A Faithful Knowledge Base Embedding Based on Convex Optimization

Knowledge base (KB) embeddings aim at combining the capability of classical knowledge graph embeddings to generalize the information present in facts, the ABox, with conceptual knowledge represented in an ontology language, the TBox. Several authors have recently explored the idea of mapping concepts to convex regions in a vector space. This is useful to represent hierarchies, typically present in TBoxes, since more general concepts can be mapped to larger regions, containing those regions associated with more specific concepts. However, the power of convexity is rarely leveraged during the actual learning tasks. Here, we introduce BoxLitE, a KB embedding model for DL-Lite$^{\mathcal{H}}$ that allows for convex optimization. We show that for any satisfiable DL-Lite$^{\mathcal{H}}$ KB, there is a BoxLitE embedding that is a weakly faithful model. As a proof of concept, we show how to formulate the KB embedding task as a convex optimization problem and how to obtain embeddings with such desirable faithfulness properties.

cs.AI↗

arXiv2024

Relations between several topologies obtained by the ideal of countable sets

The main goal of this paper is to investigate relations between topologies obtained by: $θ$-open sets, $ω$-open sets, $θ_ω$-open sets, local function, and local closure function with ideal of the countable sets. As the result we will obtain some new the relations which hold in general, and, as the ultimate goal, equality of the topology of $ω$-open sets and topology obtained by the local function with ideal of countable sets.

math.GN↗

arXiv2024

Closed sets in a generalization of the Alexandrov cube

We continue work on the topology obtained by the convergence $λ_{ls}$, which started in \cite{KuPaCZ}, and further investigated in \cite{KuPaFil19}. The main goal is to describe the closed sets and closure operator by the family of its minimal elements, with the accent on complete Boolean algebras satisfying countable chain condition.

math.GN↗

arXiv2023

On topology expansion using ideals

Topologies can be expanded with the help of ideals, using the local function, an operator resembling the closure of a set. The aim of this paper is to define the ideals which enable us to create this topology $τ^{*}$ on $X$ simultaneously making a specific set $A\subseteq X$ open in $τ^{*}$. We study certain properties of $τ^{*}$, especially under the assumption that $A$ is a preopen set. Further, we reflect on the ideal topological space in which the ideal is generated by a chosen family of dense sets. Here we prove that the generated topology by this ideal is submaximal, but not maximal connected.

math.GN↗

arXiv2023

ExpressivE: A Spatio-Functional Embedding For Knowledge Graph Completion

Knowledge graphs are inherently incomplete. Therefore substantial research has been directed toward knowledge graph completion (KGC), i.e., predicting missing triples from the information represented in the knowledge graph (KG). KG embedding models (KGEs) have yielded promising results for KGC, yet any current KGE is incapable of: (1) fully capturing vital inference patterns (e.g., composition), (2) capturing prominent patterns jointly (e.g., hierarchy and composition), and (3) providing an intuitive interpretation of captured patterns. In this work, we propose ExpressivE, a fully expressive spatio-functional KGE that solves all these challenges simultaneously. ExpressivE embeds pairs of entities as points and relations as hyper-parallelograms in the virtual triple space $\mathbb{R}^{2d}$. This model design allows ExpressivE not only to capture a rich set of inference patterns jointly but additionally to display any supported inference pattern through the spatial relation of hyper-parallelograms, offering an intuitive and consistent geometric interpretation of ExpressivE embeddings and their captured patterns. Experimental results on standard KGC benchmarks reveal that ExpressivE is competitive with state-of-the-art KGEs and even significantly outperforms them on WN18RR.

cs.LG↗

arXiv2022

Various types of continuity and their interpretations in ideal topological spaces

This paper is a continuation of work started in \cite{njampavcont} on preserving continuity in ideal topological spaces. We will deal with $θ$-continuity and weak continuity and give their translations in ideal topological spaces. As consequences of those results, we will prove that every $θ$-continuous function is continuous if topologies are generated by $θ$-open sets and we will give an example of weakly continuous function which is not $τ_θ$-continuous. This will complete the diagram of relations between continuous, $τ_θ$-continuous, $θ$-continuous, weakly continuous and faintly continuous functions.

math.GN↗

arXiv2021

On preserving continuity in ideal topological spaces

We present some sufficient conditions for continuity of the mapping $f:\langle X,τ_X^*\rangle \to \langle Y,τ_Y^*\rangle$, where $τ_X^*$ and $τ_Y^*$ are topologies induced by the local function on $X$ and $Y$, resp. under the assumption that the mapping from $\langle X, τ_X \rangle$ to $\langle Y, τ_Y \rangle$ is continuous. Further, we consider open and closed functions in this matter, as we state the cases in which the open (or closed) mapping is being preserved through the "idealisation" of both domain and codomain. Through several examples we illustrate that the conditions we considered can not be weakened.

math.GN↗

arXiv2018

The Left, the Right and the Sequential Topology on Boolean Algebras

For the algebraic convergence $λ_{\mathrm{s}}$, which generates the well known sequential topology $τ_s$ on a complete Boolean algebra ${\mathbb B}$, we have $λ_{\mathrm{s}}=λ_{\mathrm{ls}}\cap λ_{\mathrm{li}}$, where the convergences $λ_{\mathrm{ls}}$ and $λ_{\mathrm{li}}$ are defined by $λ_{\mathrm{ls}}(x)=\{ \limsup x\}\!\uparrow$ and $λ_{\mathrm{li}}(x)=\{ \liminf x\}\!\downarrow$ (generalizing the convergence of sequences on the Alexandrov cube and its dual). We consider the minimal topology $\mathcal{O}_{\mathrm{lsi}}$ extending the (unique) sequential topologies $\mathcal{O}_{λ_{\mathrm{ls}}}$ (left) and $\mathcal{O}_{λ_{\mathrm{li}}}$ (right) generated by the convergences $λ_{\mathrm{ls}}$ and $λ_{\mathrm{li}}$ and establish a general hierarchy between all these topologies and the corresponding a priori and a posteriori convergences. In addition, we observe some special classes of algebras and, in particular, show that in $(ω,2)$-distributive algebras we have $\lim_{{\mathcal O}_{\mathrm{lsi}}}=\lim_{τ_{\mathrm{s}} }=λ_{\mathrm{s}}$, while the equality $\mathcal{O}_{\mathrm{lsi}}=τ_s$ holds in all Maharam algebras. On the other hand, in some collapsing algebras we have a maximal (possible) diversity.

math.GN↗

arXiv2013

A convergence on Boolean algebras generalizing the convergence on the Aleksandrov cube

We compare the forcing related properties of a complete Boolean algebra B with the properties of the convergences $λ_s$ (the algebraic convergence) and $λ_{ls}$ on B generalizing the convergence on the Cantor and Aleksandrov cube respectively. In particular we show that $λ_{ls}$ is a topological convergence iff forcing by B does not produce new reals and that $λ_{ls}$ is weakly topological if B satisfies condition $(\hbar)$ (implied by the ${\mathfrak t}$-cc). On the other hand, if $λ_{ls}$ is a weakly topological convergence, then B is a $2^{\mathfrak h}$-cc algebra or in some generic extension the distributivity number of the ground model is greater than or equal to the tower number of the extension. So, the statement "The convergence $λ_{ls}$ on the collapsing algebra $B=\ro ((ω_2)^{<ω})$ is weakly topological" is independent of ZFC.

math.GN↗