1. A game theoretical model for the stimulation of public cooperation in environmental collaborative governanceYinhai Fang, Matjaž Perc, Hui Zhang, 2022, izvirni znanstveni članek Opis: Digital technologies provide a convenient way for the public to participate in environmental governance. Therefore, by means of a two-stage evolutionary model, a new mechanism for promoting public cooperation is proposed to accomplish environmental collaborative governance. Interactive effects of government-enterprise environmental governance are firstly explored, which is the external atmosphere for public behaviour. Second, the evolutionary dynamics of public behaviour is analysed to reveal the internal mechanism of the emergence of public cooperation in environmental collaborative governance projects. Simulations reveal that the interaction of resource elements between government and enterprise is an important basis for environmental governance performance, and that governments can improve this as well as public cooperation by increasing the marginal governance propensity. Similarly, an increase in the government's fixed expenditure item of environmental governance can also significantly improve government-enterprise performance and public cooperation. And finally, the effect of government's marginal incentive propensity on public environmental governance is moderated by enterprises' marginal environmental governance propensity, so that simply increasing the government's marginal incentive propensity cannot improve the evolutionary stable state of public behaviour under the scenario where enterprises’ marginal environmental governance propensity is low. Ključne besede: game theory, human behaviour, cooperation, mathematical model, common goods Objavljeno v DKUM: 28.05.2024; Ogledov: 4; Prenosov: 0 |
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3. Extended matrix norm method : applications to bimatrix games and convergence resultsBurhaneddin İzgi, Murat Özkaya, Nazım Kemal Üre, Matjaž Perc, 2023, izvirni znanstveni članek Opis: In this paper, we extend and apply the Matrix Norm (MN) approach to the nonzero-sum bimatrix games. We present preliminary results regarding the convergence of the MN approaches. We provide a notation for expressing nonzero-sum bimatrix games in terms of two matrix games using the idea of separation of a bimatrix game into two different matrix games. Next, we prove theorems regarding boundaries of the game value depending on only norms of the payoff matrix for each player of the nonzero-sum bimatrix game. In addition to these, we refine the boundaries of the game value for the zero/nonzero sum matrix games. Therefore, we succeed to find an improved interval for the game value, which is a crucial improvement for both nonzero and zero-sum matrix games. As a consequence, we can solve a nonzero-sum bimatrix game for each player approximately without solving any equations. Moreover, we modify the inequalities for the extrema of the strategy set for the nonzero-sum bimatrix games. Furthermore, we adapt the min-max theorem of the MN approach for the nonzero-sum bimatrix games. Finally, we consider various bimatrix game examples from the literature, including the famous battle of sexes, to demonstrate the consistency of our approaches. We also show that the repeated applications of Extended Matrix Norm (EMN) methods work well to obtain a better-estimated game value in view of the obtained convergence results. Ključne besede: game theory, nonzero sum game, bimatrix game, matrix norms, battle of sexes, convergence Objavljeno v DKUM: 15.04.2024; Ogledov: 202; Prenosov: 234 Celotno besedilo (838,66 KB) Gradivo ima več datotek! Več... |
4. Generalized cut method for computing Szeged-like polynomials with applications to polyphenyls and carbon nanoconesSimon Brezovnik, Niko Tratnik, 2023, izvirni znanstveni članek Opis: Szeged, Padmakar-Ivan (PI), and Mostar indices are some of the most investigated distance-based Szeged-like topological indices. On the other hand, the polynomials related to these topological indices were also introduced, for example the Szeged polynomial, the edge- Szeged polynomial, the PI polynomial, the Mostar polynomial, etc. In this paper, we introduce a concept of the general Szeged-like polynomial for a connected strength-weighted graph. It turns out that this concept includes all the above mentioned polynomials and also infinitely many other graph polynomials. As the main result of the paper, we prove a cut method which enables us to efficiently calculate a Szeged-like polynomial by using the corresponding polynomials of strength-weighted quotient graphs obtained by a partition of the edge set that is coarser than ▫$\Theta^*$▫-partition. To the best of our knowledge, this represents the first implementation of the famous cut method to graph polynomials. Finally, we show how the deduced cut method can be applied to calculate some Szeged-like polynomials and corresponding topological indices of para-polyphenyl chains and carbon nanocones. Ključne besede: graph theory, carbon nanocone, topological indices Objavljeno v DKUM: 25.03.2024; Ogledov: 123; Prenosov: 3 Povezava na celotno besedilo |
5. Home gardening and food security concerns during the COVID-19 pandemicMaja Turnšek, S. L. Gangenes Skar, Marit Piirman, Ragnheidur Thorarinsdottir, Martina Bavec, Ranka Junge-Berberovic, 2022, izvirni znanstveni članek Opis: At times of crisis, home gardening has often been sought out as a potential solution for threats to food security and as a measure to increase socio-psychological effects, such as public sense of self-efficacy, trust in the government and care for one’s wellbeing. The objective of this study was to investigate if home gardening increased during the COVID-19 pandemic in the spring/summer of 2020 and to provide socio-psychological insights into the explanatory factors of such an increase. An explanatory theoretical model of home gardening was proposed and tested to analyse whether home gardening is correlated to food security concerns, and if so, to what extent. A nonrepresentative survey was conducted in five European countries (Slovenia, Norway, Estonia, Switzerland, and Iceland) using snowball sampling via social media networks, reaching 1144 participants. The results showed the pandemic did prove to be an important psychological push towards home gardening prompted by food security concerns. Measured as loose as introducing at least one new gardening activity during COVID-19, this study found an approximately 10% increase in home gardening during the first wave of COVID-19 in the sample population, which was skewed towards educated, female, middle-class Europeans. Ključne besede: food security, home gardening, COVID-19, food security concerns, wellbeing, behavioural change, protection motivation theory Objavljeno v DKUM: 16.01.2024; Ogledov: 196; Prenosov: 7 Celotno besedilo (2,27 MB) Gradivo ima več datotek! Več... |
6. Quadrillion F-theory compactifications with the exact chiral spectrum of the standard modelMirjam Cvetič, James Halverson, Ling Lin, Mingqiang Liu, Jianjun Paul Tian, 2019, izvirni znanstveni članek Opis: We present O(10(15)) string compactifications with the exact chiral spectrum of the standard model of particle physics. This ensemble of globally consistent F-theory compactifications automatically realizes gauge coupling unification. Utilizing the power of algebraic geometry, all global consistency conditions can be reduced to a single criterion on the base of the underlying elliptically fibered Calabi-Yau fourfolds. For toric bases, this criterion only depends on an associated polytope and is satisfied for at least O(10(15)) bases, each of which defines a distinct compactification. Ključne besede: FLUX, F-theory, string compactifications, chiral spectrum Objavljeno v DKUM: 23.10.2023; Ogledov: 404; Prenosov: 11 Celotno besedilo (184,32 KB) Gradivo ima več datotek! Več... |
7. Constraints on standard model constructions in F-theoryMirjam Cvetič, James Halverson, Ling Lin, Cody Long, 2020, izvirni znanstveni članek Opis: We argue that the following three statements cannot all be true: (i) our vacuum is a type IIB/F-theory vacuum at moderate to large h(1,1); (ii) the alpha' expansion is controlled via the supergravity approximation, a la the Kachru-Kallosh-Linde-Trivedi and Large Volume scenarios; and (iii) there are no additional gauged sectors from 7-branes. Since nearly all known globally consistent F-theory models with the exact chiral spectrum of the Standard Model and gauge coupling unification occur at moderate h(1,1), this finding calls for new moduli stabilization scenarios or/and a rich 7-brane dark sector. Ključne besede: brane worlds, compactification, string theory Objavljeno v DKUM: 23.10.2023; Ogledov: 380; Prenosov: 11 Celotno besedilo (292,32 KB) Gradivo ima več datotek! Več... |
8. Geometric unification of Higgs bundle vacuaMirjam Cvetič, Jonathan J. Heckman, Thomas B. Rochais, Ethan Torres, Gianluca Zoccarato, 2020, izvirni znanstveni članek Opis: Higgs bundles are a central tool used to study a range of intersecting brane systems in string compactifications. Solutions to the internal gauge theory equations of motion for the corresponding worldvolume theories of brans give rise to different low energy effective field theories. This has been heavily used in the study of M-theory on local G(2) spaces and F-theory on local elliptically fibered CalabiYau fourfolds. In this paper we show that the 3D N = 1 effective field theory defined by M-theory on a local spin(7) space unifies the Higgs bundle data associated with 4D N = 1 M- and F-theory vacua. This 3D system appears as an interface with finite thickness between different 4D vacua. We develop the general formalism of M-theory on such local spin(7) spaces and build explicit interpolating solutions. This provides a complementary local gauge theory analysis of a recently proposed approach to constructing spin(7) spaces from generalized connected sums. Ključne besede: F-theory, Higgs, M-theory, field theories, spin spices Objavljeno v DKUM: 23.10.2023; Ogledov: 390; Prenosov: 11 Celotno besedilo (1,06 MB) Gradivo ima več datotek! Več... |
9. String Universality and Non-Simply-Connected Gauge Groups in 8DMirjam Cvetič, Markus Dierigl, Ling Lin, Hao Y. Zhang, 2020, izvirni znanstveni članek Opis: We present a consistency condition for 8D N 1 supergravity theories with nontrivial global structure G=Z for the non-Abelian gauge group, based on an anomaly involving the Z 1-form center symmetry. The interplay with other swampland criteria identifies the majority of 8D theories with gauge group G=Z, which have no string theory realization, as inconsistent quantum theories when coupled to gravity. While this condition is equivalent to geometric properties of elliptic K3 surfaces in F-theory compactifications, it constrains the unexplored landscape of gauge groups in other 8D string models. Ključne besede: supergravity theories, string theory, 8D string models Objavljeno v DKUM: 16.10.2023; Ogledov: 453; Prenosov: 15 Celotno besedilo (207,17 KB) Gradivo ima več datotek! Več... |
10. Yukawa hierarchies in global F-theory modelsMirjam Cvetič, Ling Lin, Mingqiang Liu, Hao Y. Zhang, Gianluca Zoccarato, 2020, izvirni znanstveni članek Opis: We argue that global F-theory compactifications to four dimensions gener- ally exhibit higher rank Yukawa matrices from multiple geometric contributions known as Yukawa points. The holomorphic couplings furthermore have large hierarchies for generic complex structure moduli. Unlike local considerations, the compact setup realizes these features all through geometry, and requires no instanton corrections. As an example, we consider a concrete toy model with SU(5) x U(1) gauge symmetry. From the geometry, we find two Yukawa points for the 10-25-4 coupling, producing a rank two Yukawa matrix. Our methods allow us to track all complex structure dependencies of the holomorphic couplings and study the ratio numerically. This reveals hierarchies of O(10(5)) and larger on a full-dimensional subspace of the moduli space. Ključne besede: F-theory, supersymmetric effective theories Objavljeno v DKUM: 16.10.2023; Ogledov: 180; Prenosov: 11 Celotno besedilo (930,60 KB) Gradivo ima več datotek! Več... |