39 citations · 277 across the 27 of their papers we have counts for
27 papers
Characterising regular double Stone and pseudocomplemented Kleene algebras in completions of rough sets induced by reflexive relations
Jouni Järvinen, Sándor Radeleczki
We consider Kleene and Stone algebras defined on the completion DM(RS) of the ordered set of rough sets induced by a reflexive relation. We focus on the cases where the completion…
Nelson algebras, residuated lattices and rough sets: A survey
Jouni Järvinen, Sándor Radeleczki, Umberto Rivieccio
Over the past 50 years, Nelson algebras have been extensively studied by distinguished scholars as the algebraic counterpart of Nelson's constructive logic with strong negation. De…
Relational correspondences for L-fuzzy rough approximations defined on De Morgan Heyting algebras
Jouni Järvinen, Michiro Kondo
We consider fuzzy rough sets defined on De Morgan Heyting algebras. We present a theorem that can be used to obtain several correspondence results between fuzzy rough sets and fuzz…
Pseudo-Kleene algebras determined by rough sets
Jouni Järvinen, Sándor Radeleczki
We study the pseudo-Kleene algebras of the Dedekind-MacNeille completion of the ordered set of rough set determined by a reflexive relation. We characterize the cases when PBZ and…
A large octupole magnetic trap for research with atomic hydrogen
J. Ahokas, A. Semakin, J. Järvinen +12
We describe the design and performance of a large magnetic trap for storing and cooling of atomic hydrogen (H). The trap operates in the vacuum space of a dilution refrigerator at…
Defining rough sets as core-support pairs of three-valued functions
Jouni Järvinen, Sándor Radeleczki
We answer the question what properties a collection of three-valued functions on a set must fulfill so that there exists a quasiorder on such that the…
The structure of multigranular rough sets
Jouni Järvinen, Sándor Radeleczki
We study multigranulation spaces of two equivalences. The lattice-theoretical properties of so-called "optimistic" and "pessimistic" multigranular approximation systems are given.…
Defining rough sets using tolerances compatible with an equivalence
Jouni Järvinen, László Kovács, Sándor Radeleczki
We consider tolerances compatible with an equivalence on , meaning that the relational product is included in . We present the essential properties of …
Prime filter structures of pseudocomplemented Kleene algebras and representation by rough sets
Jouni Järvinen, Sándor Radeleczki
We introduce Kleene-Varlet spaces as partially ordered sets equipped with a polarity satisfying certain additional conditions. By applying Kleene-Varlet spaces, we prove that each…
Electron spin resonance study of atomic hydrogen stabilized in solid neon below 1K
Sergey Sheludiakov, Janne Ahokas, Jarno Jarvinen +4
We report on an electron spin resonance study of atomic hydrogen stabilized in a solid Ne matrices carried out at a high field of 4.6 T and temperatures below 1 K. The films of Ne,…
Dynamic Polarization and Relaxation of 75As Nuclei in Silicon at High Magnetic Field and Low Temperature
J. Järvinen, J. Ahokas, S. Sheludyakov +5
We present the results of experiments on dynamic nuclear polarization and relaxation of 75As in silicon crystals. Experiments are performed in strong magnetic fields of 4.6 T and t…
Representing regular pseudocomplemented Kleene algebras by tolerance-based rough sets
Jouni Järvinen, Sándor Radeleczki
We show that any regular pseudocomplemented Kleene algebra defined on an algebraic lattice is isomorphic to a rough set Kleene algebra determined by a tolerance induced by an irred…
Dynamic nuclear polarization and relaxation of H and D atoms in solid mixtures of hydrogen isotopes
S. Sheludiakov, J. Ahokas, J. Järvinen +5
We report on a study of Dynamic Nuclear Polarization and electron and nuclear spin relaxation of atomic hydrogen and deuterium in solid molecular matrices of H, D, and…
ESR study of atomic hydrogen and tritium in solid T and T:H matrices below 1K
S. Sheludiakov, J. Ahokas, J. Järvinen +6
We report on the first ESR study of atomic hydrogen and tritium stabilized in a solid T and T:H matrices down to 70mK. The concentrations of T atoms in pure T…
Identical Spin Rotation Effect and Electron Spin Waves in Quantum Gas of Atomic Hydrogen
L. Lehtonen, O. Vainio, J. Ahokas +7
We present an experimental study of electron spin waves in atomic hydrogen gas compressed to high densities of cm at temperatures ranging from 0.26 t…
Microscopic control of Si nuclear spins near phosphorus donors in silicon
J. Järvinen, D. Zvezdov, J. Ahokas +11
We demonstrate an efficient control of Si nuclear spin orientation for specific lattice sites near P donors in silicon crystals at temperatures below 1 K and in high…
Tolerances induced by irredundant coverings
Jouni Järvinen, Sándor Radeleczki
In this paper, we consider tolerances induced by irredundant coverings. Each tolerance on determines a quasiorder by setting if and only if $R…
Monteiro spaces and rough sets determined by quasiorder relations: Models for Nelson algebras
Jouni Järvinen, Sándor Radeleczki
Rough sets induced by quasiorders appear in several constructions using binary relations in computer science. In this paper, a structural characterisation of rough sets induced by…
Efficient Dynamic Polarization of Phosphorus Nuclei in Silicon in Strong Magnetic Fields and Low Temperatures
J. Järvinen, D. Zvezdov, J. Ahokas +11
We demonstrate that the dynamic nuclear polarization (DNP) of phosphorus donors in silicon can be very effective in a magnetic field of 4.6 T and at temperatures below 1 K. The DNP…
Characterizing intermediate tense logics in terms of Galois connections
Wojciech Dzik, Jouni Järvinen, Michiro Kondo
We propose a uniform way of defining for every logic intermediate between intuitionistic and classical logics, the corresponding intermediate minimal tense logic ${\sf LK…
Representing distributive lattices with Galois connections in terms of rough sets
Wojciech Dzik, Jouni Järvinen, Michiro Kondo
This paper studies expansions of bounded distributive lattices equipped with a Galois connection. We introduce GC-frames and canonical frames for these algebras. The complex algebr…
Rough sets determined by tolerances
Jouni Järvinen, Sándor Radeleczki
We show that for any tolerance on , the ordered sets of lower and upper rough approximations determined by form ortholattices. These ortholattices are completely distrib…
Intuitionistic logic with two Galois connections combined with Fischer Servi axioms
Wojciech Dzik, Jouni Järvinen, Michiro Kondo
Earlier, the authors introduced the logic IntGC, which is an extension of intuitionistic propositional logic by two rules of inference mimicking the performance of Galois connectio…
Information completeness in Nelson algebras of rough sets induced by quasiorders
Jouni Järvinen, Piero Pagliani, Sándor Radeleczki
In this paper, we give an algebraic completeness theorem for constructive logic with strong negation in terms of finite rough set-based Nelson algebras determined by quasiorders. W…