Finite Geometry Research Group at Eötvös University

(this homepage is maintained by Peter Sziklai)

The Finite Geometry research group was founded informally by Tamás Szőnyi in the late 80's of the last century.
The topics covered by the members are

- Galois geometries
- arcs, caps, blockings sets, semiovals, nuclei
- coding theory
- stability questions
- polynomials over finite fields.

Below you can find the list of some of the participants with links to their homepages,
some links to friends, colleagues and other research groups and
the program of our Seminar on Finite Geometry, from 2002 spring.

Program of this semester (2011 Fall):

Some of the participants (current and late):

Some links

Program of 2011 Spring

25 Febr: Z. L. Nagy: On the sumset partition problem
4 March: Sz. L. Fancsali:
11 March: M. Takats: A generalization of the direction problem
18 March: I. Kovacs: On covering systems of finite abelian groups
25 March: Gy. Károlyi: On the existence of pairs with prescribed distance
1 Apr: A. Blokhuis: On the uniqueness of the Brouwer60 graph
8 Apr: C. Kiss-Toth: Sudoku and finite geometries
15 Apr: T. Heger: The Lemma of Tangents reformulated (article of Kris Coolsaet)
29 Apr: T. Szonyi: On small blocking sets
6 May: J. Ruff: Rose-window graphs
20 May: N. Harrach: Almost blocking sets and almost coverings
G. Meszaros: Arcs on Hall-planes

Program of 2010 Fall

24 Sept: B. Csajbok: Semiovals and semiarcs on finite planes
1 Oct: I. Kovács: On regular Cayley maps on dihedral groups
8 Oct: N. Harrach: On t-fold (n-k)-blocking sets of PG(n, q)
15 Oct: Gy. Kiss: Semiovals which are constructed as the union of conics
22 Oct: A. Blokhuis: Maximal cocliques of the Kneser-graph of point-hyperplane
flags in projective spaces
5 Nov: T. Héger: Regular configurations in projective planes
12 Nov: J. D. Beule: Small (n-1)-covers of the polar spaces Q+(2n+1,q) and H(2n+1,q^2)
19 Nov: P. Csikvári: Polynomial and multilinear methods
26 Nov: P. Sziklai: About the Nullstellensatz
3 Dec: M. Takats: Maximal integral point sets in affine planes over finite fields
10 Dec: G. V. d. Voorde: Stopping sets in LDPC codes and sets without tangents in finite projective planes
17 Dec: Z. L. Nagy: Permutations over cyclic groups

Program of 2010 Spring

19 Febr: G Nagy: On the prime power conjecture
26 Febr:  N. Harrach: t-fold blocking sets
5  March: Sz.L. Fancsali: Direction sets
12 March: Gy. Kiss: The mutual position of conics
26 March: Gy. Kiss: MES
9 Apr: T. Héger: Zarankiewicz's problem (a paper of Steven Roman)
16 Apr: P. Sziklai: Directions and perfect sumsets
30 Apr: Angelo Sonnino: Projective k-arcs and 2-level sharing schemes,
G. Korchmaros: 3-nets embedding in a projective plane
7 May: A. Blokhuis: On the structure of 3-nets embedded in a projective plane
14 May: Leo Storme: Minimal codewords in Reed-Muller codes
8 Jun: T. Penttila: Groups of Lie type as a source of finite geometry

Program of 2009 Fall

18 Sept: T. Szőnyi: Hilton-Milner theorems for vector spaces
25 Sept: N. Harrach: On high dimensional blocking sets
2 Oct: T. Szőnyi: On the chromatic number of the Kneser graph of parameter n=2
9 Oct: Gy. Károlyi: The recent proof of the Snevily conjecture
16 Oct:T. Szőnyi: On the chromatic number of the Kneser graph of parameter n=2k, cont'd
6 Nov: G. Kéri: On orthogonal arrays, covering arrays and the nonlinear MDS conjecture
13 Nov:  Jan De Beule (Gent, Belgium): On (Partial) ovoids and (partial) m-ovois of Q-(5,q)
20 Nov:  Jan De Beule
27 Nov:  Valentina Pepe (Gent, Belgium): Erdos-Ko-Rado theorems for dual polar spaces
4   Dec:  Anja Hallez (Gent, Belgium): Sets of generators blocking all generators in finite classical polar spaces
11 Dec:  P. Csikvári: Independent sets in graphs

Program of 2009 Spring

20 Febr: G. Kéri
27 Febr:      conference
 6  March: G. Kéri
13 March: Gy. Kiss: On the size of semiovals
20 March: P. Sziklai: Codewords of small weight
27 March: P. Sziklai, cont'd; M. Takats: Generalized caps
3 Apr: Z.L. Nagy
17 Apr: cancelled
24 Apr:  Aart Blokhuis
15 May: P. Csikvári: On a proof of Burnside's theorem

Program of 2008 Fall

19 Sept: A. Gács: Extendability of MDS codes
  3 Oct: G. Nagy:  Bol-loops of expontent 2
10 Oct: S. Ball (UPC, Barcelona): Codes, bounds and blocking sets
17 Oct: Gy. Károlyi: Exterior algebra methods
 7 Nov: Jan De Beule (Gent): Particular facts about finite classical generalized quadrangles
14 Nov: B. Montagh: Graph constructions
21 Nov: G. Pluhár: Islands on the triangular lattice
28 Nov: M. Korom: Blocking lines exterior to a quadric, I
 5  Dec: S. Vidor: Blocking lines exterior to a quadric, II
12 Dec: A Gács: On the discrete Kakeya problem

Program of 2008 Spring
15 Febr: A. Gacs: A 70 years old problem
22 Febr: Gy. Kiss: Sudoku and finite geometry
29 Febr: K. Horvath: Norm graphs
  7 March: A Gacs: Embeddings of partial projective planes
14 March: B. Csajbok: Upper bounds on the number of lines in maximal cliques
28 March: Leo Storme (Gent): Blocking sets in PG(3,q)
 4 Apr: Sz. Fancsali: On minimal t-fold blocking sets
11 Apr:  I. Stuhl: Steiner loops and their small extensions
18 Apr: E. Adamcsek: 1- and t-factorisations of the complete graph
25 Apr: Z. Gyenis: Constructions of maximal arcs
16 May: B. Csajbok: Maximal intersecting systems

Program of 2007 Fall
21 Sept: T. Heger:  Configurations
  5 Oct: K. Kutnar: A complete classification of cubic symmetric graphs of girth 6
12 Oct: P. Csikvari: Line-free sets in AG(n,3) and the SET game
19 Oct: P. Csikvari: Sumsets with square elements I.
26 Oct: P. Csikvari: Sumsets with square elements II.
  9 Nov: N. Harrach: (New) blocking sets in AG(2,q)
16 Nov: S. Miklavic: Consistent polygons in configurations
23 Nov: M. Weiner: Quantum information theory and finite projective planes
30 Nov: Gy. Kiss: On semiovals
  7 Dec: P. Sziklai: The punctured Nullstellensatz
14 Dec: T. Szonyi: Codes and curves

Program of 2007 Spring

16 Febr:   Gy. Kiss: Large Cayley graphs with given degree and diameter
23 Febr:    Sz. Fancsali: Minimal weight words of codes of projective planes
2   March: Zs. Tuza: Hypergraph coloring and projective planes
9   March: A Gacs: Directions in the plane and generalizations
23 March: P. Sziklai: On Vandermonde sets
30 March:  Z.L. Nagy: Directions in the 3-space
13 April:  B. Acs: The Hoffman-Singleton paper
20 April: D. Pinter: Groebner bases and the Babai-Frankl conjecture I.
27 April: D. Pinter: Groebner bases and the Babai-Frankl conjecture II.
11 May: 
18 May:  T. Heger: Extremal graphs and finite geometries

Program of 2006 Fall
29 Sept: A Gacs: On random constructions
  6 Oct: Gy. Kiss: Semiovals
13 Oct: Aart Blokhuis: Button madness
27 Oct: A Gacs & T. Szonyi: Directions determined by a pointset in AG(2,q)
10 Nov: A. Gacs: continued
17 Nov: Jan De Beule (Gent): Generalized quadrangles 1
24 Nov: Jan De Beule (Gent): Generalized quadrangles 2
  1 Dec: Jan De Beule (Gent): Generalized quadrangles 3
  8 Dec:  Simeon Ball  (Barcelona, UPC)
15 Dec:  A. Szeker

Program of 2006 Spring

24 Febr: Gy. Kiss: 1-factorisations
  3 March: A. Gacs: Introduction to polar spaces 1
10 March: Zs. Weiner: Introduction to polar spaces 2
24 March: Zs. Weiner: Polar spaces and generalized quadrangles
31 March: Gabor Bartok
  7 April:  Szabolcs Fancsali
28 April:  Zs. Weiner: Generalized quadrangles and ovoids 1
12 May:  Gyula Karolyi
19 May:  Zs.  Weiner: Generalized quadrangles and ovoids 2

Program of 2005 Fall:
23 Sept.: Istvan Kovacs: On nonexistence of semiovals
30 Sept.: Tamas Szonyi:  Stability of blocking sets
14 Oct.:  Andras Gacs: Point sets with 0 mod p intersections
21 Oct.:  Zsuzsa Weiner: Stability of even pointsets
28 Oct.:  Gyula Karolyi: Combinatorial Nullstellensatz-like results
  1 Nov.:  Tamas Szonyi: Cyclic arcs
18 Nov.: Jan De Beule: On maximal partial spreads of Hermitian varieties
25 Nov.: Aart Blokhuis: TBA
2   Dec.: Andras Gacs: Applications of the combinatorial Nullstellensatz
9   Dec.: Gyorgy Kiss:  A geometric construction of large vertex transitive graphs
16 Dec.:  Peter Sziklai: TBA + pizza

Program of 2005 Spring:

Febr. 18.: Rita Vincenti: Characterizations of (varieties and) codes from the Tallini point of view
Febr. 25.: Gacs Andras: Redei polynomials in dim>2
March  4.: Nagy Gabor: Lines on algebraic surfaces
March 11.: Weiner Zsuzsa: Extendability of linear codes, and blocking sets
March 18.: Szonyi Tamas: On the size of an independent set in the Erdos-Renyi graph
Apr.   1.:  Szabo Csaba: Algebraic properties of a geometrical configuration
Apr.   8.: Hendrik Van Maldeghem:  Geometries from certain doubly transitive permutation groups
Apr.  15.: Szonyi Tamas: Applications of algebraic curves I.
Apr.  22.: Szonyi Tamas: Applications of algebraic curves II.
Apr.  29.: Szonyi Tamas: Applications of algebraic curves III.
May   6.:  Aart Blokhuis: Constructions of Bipartite Graphs from Finite Geometries
May  20.: Mengyan Csaba: TBA + pizza

Program of 2004 Fall:

Sept. 24: Sziklai Peter: (Partial) flocks of cones
Oct. 1:  Szonyi Tamas: Bounds on arcs of projective planes
Oct. 8: Kovacs Istvan: Cayley graphs of non-commutative groups
Oct. 15: Szonyi Tamas: The Segre-Korchmaros theorem and its applications
Oct. 22:       "       "                 "  continued
Oct. 29: Gacs Andras: Regular semiovals
Nov. 5:  NO SEMINAR
Nov. 12: Leo Storme (Gent):  Shortened incidence matrices of PG(2,p)
Nov. 19: Aart Blokhuis (Eindhoven)
Nov. 26:  Stefan Dodunekov: Codes and geometry
Dec. 3:  Gyorey Bernadett: Planar functions
Dec. 10: Gacs Andras: Applications of finite geometry (in graph theory)
Dec. 17:    "      "                  "  continued

Program of 2004 Spring:

febr. 20: Sziklai Peter: On small blocking sets
febr. 27: NO TALK
marc. 5: Sziklai Peter: On small blocking sets
marc. 12: Sziklai Peter: On small blocking sets
marc. 19: Nagy Gabor: Codes and Moufang loops
apr. 16: Szonyi Tamas: A paper of Tallini
apr. 23: Fancsali Szabolcs: Segre varieties
apr. 30: Ruff Janos: Semiovals of index 3

Program of 2003 Fall:

19 Sept: Szonyi Tamas: n-e.c. graphs and affine planes
26 Sept: Szonyi Tamas: Flocks of cones: star flocks
  3 Oct:   Szonyi Tamas: Flocks of cones: star flocks (cont'd)
10 Oct:   Gacs Andras:  Introduction to ovoids, I
31 Oct:   Gacs Andras:  Introduction to ovoids, II
  7 Nov:  Sandy Ferret: Whether caps are parts of ovoids
14 Nov    Patrick Govaerts: Mixed partial spreds and MAXMOLS
21 Nov   Simeon Ball: Permutation polynomials arising from spreads
28 Nov   Patrick Govaerts: Applications of Ball's 1 mod p result for
                             ovoids of Q(4,q)
  5 Dec    Kovacs Istvan: Some problems related to Schur rings
12 Dec    Weiner Zsuzsa: SETs and spreads

Program of 2003 Spring:

28 Febr   :    Szonyi Tamas: On the number of lines meeting a (q+2)-set
7   March:   Aart Blokhuis: External points determining passant lines
14 March:   Aart Blokhuis:  On blocking sets of size 3(p+1)/2
21 March:   Szonyi Tamas: t-fold blocking sets
28 March:   Szonyi Tamas:     "          "           "    ,  continued
4     Apr:       Gacs Andras: Planar functions
11  Apr:       Kiss Gyorgy: Semiovals with a large collinear subset
18  Apr:        SPRING HOLIDAYS
25  Apr:        Kovacs Istvan:  Circulant graphs on 2^m  points, m is up to 5
2   May:        NO SEMINAR
9   May:        NO SEMINAR
16 May:        Weiner Zsuzsa: On blocking sets

Program of  2002 Fall:

20 Sept : Alessandro Siciliano: Flocks of hyperbolic quadrics
27 Sept : Szonyi Tamas: Flocks, herds and clans
4 Oct   : Kiss Gyorgy: On quadratic surfaces
11 Oct  : Szonyi Tamas: On quadratic surfaces, continued
18 Oct  : Nagy Gabor: The geometry of orthogonal groups
25 Oct  : Gacs Andras: Line-sets and spreads in PG(3,q)
1 Nov   : NO SEMINAR
8 Nov   :  Gacs A.-Szonyi T.-Weiner Zs.: Large minimal blocking sets in planes of non-square order
15 Nov  : Leo Storme:  Codes meeting the Griesmer -bound and minihypers
22 Nov  : Nagy Gabor: Extra-special groups and loops
29 Nov:  Aart Blokhuis: Small additive quaternary codes and linesets in PG(n,2)
6 Dec    : Kovacs Istvan: On the properties of the Paley graph
13 Dec  : Pinter Domotor: Secret-sharing schemes

Program of 2002 Spring:

22 Feb P 13.30-15.00  Dragan Marusic (Ljubljana)
25 Feb H 15.30-17.00  Sziklai Peter
1 Mar  P !!! 13.30-15.00 Tichler Krisztian
 11 Mar H 15.30-17.00  Szonyi Tamas
22 Mar P 13.30-15.00  instead: march 18 H 15.30-17.00: Korchmaros Gabor
25 Mar H 15.30-17.00  SPRING HOLIDAYS
5 Apr P 13.30-15.00  Szonyi Tamas
8 Apr   H 15.30-17.00  Revai Nora
19 Apr  P 13.30-15.00  Weiner Zsuzsa
22 Apr  H 15.30-17.00  Weiner Zsuzsa
3 May   P 13.30-15.00  Kiss Gyorgy
6 May   H 15.30-17.00  Ruff Janos
17 May  P 13.30-17.00  Simeon Ball