Joško Mandić - Academia.edu (original) (raw)

Papers by Joško Mandić

Research paper thumbnail of Flag-transitive and point-imprimitive symmetric designs with λ ≤ 10

Journal of Combinatorial Theory, Series A, 2022

Research paper thumbnail of Groups \(S_n \times S_m\) in construction of flag-transitive block designs

Glasnik Matematicki, 2021

In this paper, we observe the possibility that the group \(S_{n}\times S_{m}\) acts as a flag-tra... more In this paper, we observe the possibility that the group \(S_{n}\times S_{m}\) acts as a flag-transitive automorphism group of a block design with point set \(\{1,\ldots ,n\}\times \{1,\ldots ,m\},4\leq n\leq m\leq 70\). We prove the equivalence of that problem to the existence of an appropriately defined smaller flag-transitive incidence structure. By developing and applying several algorithms for the construction of the latter structure, we manage to solve the existence problem for the desired designs with \(nm\) points in the given range. In the vast majority of the cases with confirmed existence, we obtain all possible structures up to isomorphism.

Research paper thumbnail of Geršgorinova lokacija spektra i primjene

In the paper, we consider the problem of determining a subset of the complex plane which contains... more In the paper, we consider the problem of determining a subset of the complex plane which contains all eigenvalues of the given complex matrix. We point to several applications of the gained eigenvalue inclusion sets in different branches of applied mathematics.

Research paper thumbnail of Some new primitive symmetric designs

All primitive symmetric designs with at most 255 points have been constructed and classified (S. ... more All primitive symmetric designs with at most 255 points have been constructed and classified (S. Braic, PhD thesis, 2007). In this research we either prove the non-existence or give explicit construction of some symmetric designs with primitive automorphism groups of higher degree. The method of design construction is based on an automorphism group action, and on the theory of difference sets, multiplier theorems in particular. It involves programming and wide-range computations. We make use of software package GAP, the well-known system for computational group theory, and the library of primitive groups which it contains.

Research paper thumbnail of Primitive Symmetric Designs Having Up to 2500 Points

Research paper thumbnail of Matematička igra RasTpad

Acta mathematica Spalatensia. Series didactica, 2020

U ovom radu predstavit će se igra RasTpad, autora Krune Matića, te dati njena matematička analiza... more U ovom radu predstavit će se igra RasTpad, autora Krune Matića, te dati njena matematička analiza koja opisuje strategiju pronalaska rješenja igre i osnovni pristup analizi broja rješenja s obzirom na zadano početno stanje tablice igre.

Research paper thumbnail of On the existence of Hadamard difference sets in groups of order 400

Advances in Mathematics of Communications, 2016

Research paper thumbnail of Torus-like continua which are not self-covering spaces

Topology and its Applications, 2005

Research paper thumbnail of Primitive symmetric designs with prime power number of points

Journal of Combinatorial Designs, 2009

In this paper we either prove the non‐existence or give explicit construction of primitive symmet... more In this paper we either prove the non‐existence or give explicit construction of primitive symmetric (v, k, λ) designs with v=pm<2500, p prime and m>1. The method of design construction is based on an automorphism group action; non‐existence results additionally include the theory of difference sets, multiplier theorems in particular. The research involves programming and wide‐range computations. We make use of software package GAP and the library of primitive groups which it contains. © 2009 Wiley Periodicals, Inc. J Combin Designs 18: 141–154, 2010

Research paper thumbnail of Primitive symmetric designs with up to 2500 points

Journal of Combinatorial Designs, 2011

Research paper thumbnail of On difference sets in high exponent 2-groups

Journal of Algebraic Combinatorics, 2013

Research paper thumbnail of On the existence of difference sets in groups of order 96

Discrete Mathematics, 2007

Research paper thumbnail of One (96,20,4)-symmetric Design and related Nonabelian Difference Sets

Designs, Codes and Cryptography, 2005

Research paper thumbnail of Flag-transitive and point-imprimitive symmetric designs with λ ≤ 10

Journal of Combinatorial Theory, Series A, 2022

Research paper thumbnail of Groups \(S_n \times S_m\) in construction of flag-transitive block designs

Glasnik Matematicki, 2021

In this paper, we observe the possibility that the group \(S_{n}\times S_{m}\) acts as a flag-tra... more In this paper, we observe the possibility that the group \(S_{n}\times S_{m}\) acts as a flag-transitive automorphism group of a block design with point set \(\{1,\ldots ,n\}\times \{1,\ldots ,m\},4\leq n\leq m\leq 70\). We prove the equivalence of that problem to the existence of an appropriately defined smaller flag-transitive incidence structure. By developing and applying several algorithms for the construction of the latter structure, we manage to solve the existence problem for the desired designs with \(nm\) points in the given range. In the vast majority of the cases with confirmed existence, we obtain all possible structures up to isomorphism.

Research paper thumbnail of Geršgorinova lokacija spektra i primjene

In the paper, we consider the problem of determining a subset of the complex plane which contains... more In the paper, we consider the problem of determining a subset of the complex plane which contains all eigenvalues of the given complex matrix. We point to several applications of the gained eigenvalue inclusion sets in different branches of applied mathematics.

Research paper thumbnail of Some new primitive symmetric designs

All primitive symmetric designs with at most 255 points have been constructed and classified (S. ... more All primitive symmetric designs with at most 255 points have been constructed and classified (S. Braic, PhD thesis, 2007). In this research we either prove the non-existence or give explicit construction of some symmetric designs with primitive automorphism groups of higher degree. The method of design construction is based on an automorphism group action, and on the theory of difference sets, multiplier theorems in particular. It involves programming and wide-range computations. We make use of software package GAP, the well-known system for computational group theory, and the library of primitive groups which it contains.

Research paper thumbnail of Primitive Symmetric Designs Having Up to 2500 Points

Research paper thumbnail of Matematička igra RasTpad

Acta mathematica Spalatensia. Series didactica, 2020

U ovom radu predstavit će se igra RasTpad, autora Krune Matića, te dati njena matematička analiza... more U ovom radu predstavit će se igra RasTpad, autora Krune Matića, te dati njena matematička analiza koja opisuje strategiju pronalaska rješenja igre i osnovni pristup analizi broja rješenja s obzirom na zadano početno stanje tablice igre.

Research paper thumbnail of On the existence of Hadamard difference sets in groups of order 400

Advances in Mathematics of Communications, 2016

Research paper thumbnail of Torus-like continua which are not self-covering spaces

Topology and its Applications, 2005

Research paper thumbnail of Primitive symmetric designs with prime power number of points

Journal of Combinatorial Designs, 2009

In this paper we either prove the non‐existence or give explicit construction of primitive symmet... more In this paper we either prove the non‐existence or give explicit construction of primitive symmetric (v, k, λ) designs with v=pm<2500, p prime and m>1. The method of design construction is based on an automorphism group action; non‐existence results additionally include the theory of difference sets, multiplier theorems in particular. The research involves programming and wide‐range computations. We make use of software package GAP and the library of primitive groups which it contains. © 2009 Wiley Periodicals, Inc. J Combin Designs 18: 141–154, 2010

Research paper thumbnail of Primitive symmetric designs with up to 2500 points

Journal of Combinatorial Designs, 2011

Research paper thumbnail of On difference sets in high exponent 2-groups

Journal of Algebraic Combinatorics, 2013

Research paper thumbnail of On the existence of difference sets in groups of order 96

Discrete Mathematics, 2007

Research paper thumbnail of One (96,20,4)-symmetric Design and related Nonabelian Difference Sets

Designs, Codes and Cryptography, 2005