Skip to main content

The Use of Valuations for Classifying Point-Line Geometries

  • Conference paper
  • First Online:
Book cover Groups of Exceptional Type, Coxeter Groups and Related Geometries

Part of the book series: Springer Proceedings in Mathematics & Statistics ((PROMS,volume 82))

Abstract

A valuation is a map from the point set of a point-line geometry \({\mathcal {S}}\) to the set \({\mathbb {N}}\) of nonnegative integers satisfying a number of well-chosen axioms. These axioms are chosen in such a way that these objects are (potentially) useful for classifying certain point-line geometries that contain an isomorphic copy of \({\mathcal {S}}\) as a full subgeometry. Depending on the list of chosen axioms, different “valuation theories” can be developed. The importance of each such theory depends on the successes that can be achieved in classification problems. Valuations have been successfully used for classifying certain near polygons (in particular generalized polygons). They were also useful tools for obtaining a number of other results. The aim of this paper is to survey some of these results.

MSC2000: 51E12, 05B25.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 129.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 169.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  1. Brouwer, A.E., Cohen, A.M., Hall, J.I., Wilbrink, H.A.: Near polygons and Fischer spaces. Geom. Dedicata 49, 349–368 (1994)

    Article  MATH  MathSciNet  Google Scholar 

  2. Brouwer, A.E., Cohen, A.M., Neumaier, A.: Distance-regular graphs. In: Results in Mathematics and Related Areas (3), vol. 18. Springer, Berlin (1989)

    Google Scholar 

  3. Brouwer, A.E., Wilbrink, H.A.: The structure of near polygons with quads. Geom. Dedicata 14, 145–176 (1983)

    Article  MATH  MathSciNet  Google Scholar 

  4. Cohen, A.M., Tits, J.: On generalized hexagons and a near octagon whose lines have three points. Eur. J. Comb. 6, 13–27 (1985)

    Article  MATH  MathSciNet  Google Scholar 

  5. De Bruyn, B.: Near hexagons with four points on a line. Adv. Geom. 1, 211–228 (2001)

    Article  MATH  MathSciNet  Google Scholar 

  6. De Bruyn, B.: Near polygons. In: Frontiers in Mathematics. Birkhäuser Verlag, Basel (2006)

    Google Scholar 

  7. De Bruyn, B.: Valuations of glued near hexagons. J. Comb. Des. 15, 35–48 (2007)

    Article  MATH  Google Scholar 

  8. De Bruyn, B.: A characterization of the SDPS-hyperplanes of dual polar spaces. Eur. J. Comb. 28, 705–714 (2007)

    Article  MATH  Google Scholar 

  9. De Bruyn, B.: Dense near octagons with four points on each line, II. Adv. Geom. 7, 191–206 (2007)

    Article  MATH  MathSciNet  Google Scholar 

  10. De Bruyn, B.: An alternative definition of the notion valuation in the theory of near polygons. Electron. J. Comb. 16, 14 (2009) (Research paper 16)

    Google Scholar 

  11. De Bruyn, B.: The valuations of the near polygon \({\mathbb{G}}_n\). Electron. J. Comb. 16, 29 (2009) (Research paper 137)

    Google Scholar 

  12. De Bruyn, B.: The valuations of the near \(2n\)-gon \({\mathbb{I}}_n\). Ars Comb. 98, 321–336 (2011)

    MATH  Google Scholar 

  13. De Bruyn, B.: Dense near octagons with four points on each line, III. Ann. Comb. 15, 19–35 (2011)

    Article  MATH  MathSciNet  Google Scholar 

  14. De Bruyn, B.: Polygonal valuations. Discrete Math. 313, 84–93 (2013)

    Article  MATH  MathSciNet  Google Scholar 

  15. De Bruyn, B.: On the valuations of the near polygon \({\mathbb{H}}_n\). Preprint 2012

    Google Scholar 

  16. De Bruyn, B.: The uniqueness of a certain generalized octagon of order \((2,4)\). Preprint 2012

    Google Scholar 

  17. De Bruyn, B.: On semi-finite generalized hexagons of order \((2, t)\) and \((3, t)\) containing subhexagons. In preparation

    Google Scholar 

  18. De Bruyn, B., Vandecasteele, P.: Valuations of near polygons. Glasg. Math. J. 47, 347–361 (2005)

    Article  MATH  MathSciNet  Google Scholar 

  19. De Bruyn, B., Vandecasteele, P.: Valuations and hyperplanes of dual polar spaces. J. Com. Theory, Ser. A 112, 194–211 (2005)

    Article  MATH  Google Scholar 

  20. De Bruyn, B., Vandecasteele, P.: The valuations of the near hexagons related to the Witt designs \(S(5,6,12)\) and \(S(5,8,24)\). J. Comb. Des. 14, 214–228 (2006)

    Article  MATH  Google Scholar 

  21. De Bruyn, B., Vandecasteele, P.: The distance-2-sets of the slim dense near hexagons. Ann. Comb. 10, 193–210 (2006)

    Article  MATH  MathSciNet  Google Scholar 

  22. De Bruyn, B., Vandecasteele, P.: The valuations of the near octagon \({\mathbb{I}}_4\). Electron. J. Comb. 13, 23 (2006) (Research paper 76)

    Google Scholar 

  23. De Bruyn, B., Vandecasteele, P.: The classification of the slim dense near octagons. Eur. J. Comb. 28, 410–428 (2007)

    Article  MATH  Google Scholar 

  24. De Bruyn, B., Vandecasteele, P.: The valuations of the near octagon \({\mathbb{H}}_4\). Graphs and Combinatorics 23, 601–623 (2007)

    Article  MATH  MathSciNet  Google Scholar 

  25. De Bruyn, B., Vandecasteele, P.: The valuations of the near octagon \({\mathbb{G}}_4\). Discrete Math. 310, 755–766 (2010)

    Article  MATH  MathSciNet  Google Scholar 

  26. De Bruyn, B., Vanhove, F.: Inequalities for regular near polygons, with applications to \(m\)-ovoids. Eur. J. Comb. 34, 522–538 (2013)

    Article  MATH  Google Scholar 

  27. De Bruyn, B., Vanhove, F.: On \(Q\)-polynomial regular near \(2d\)-gons. Combinatorica (to appear)

    Google Scholar 

  28. De Medts, T., Van Maldeghem, H.: The uniqueness of a generalized hexagon of order 3 containing a subhexagon of order \((1,3)\). Discrete Math. 309, 714–720 (2009)

    Article  MATH  MathSciNet  Google Scholar 

  29. The GAP Group, GAP—Groups, Algorithms, and Programming, Version 4.4.12. http://www.gap-system.org (2008)

  30. Offer, A., Van Maldeghem, H.: Distance-\(j\) ovoids and related structures in generalized polygons. Discrete Math. 294, 147–160 (2005)

    Article  MATH  MathSciNet  Google Scholar 

  31. Pralle, H., Shpectorov, S.: The ovoidal hyperplanes of a dual polar space of rank 4. Adv. Geom. 7, 1–17 (2007)

    Article  MATH  MathSciNet  Google Scholar 

  32. Ree, R.: A family of simple groups associated with the simple Lie algebra of type \((F_{4})\). Am. J. Math. 83, 401–420 (1961)

    Article  MATH  MathSciNet  Google Scholar 

  33. Shult, E.E., Yanushka, A.: Near \(n\)-gons and line systems. Geom. Dedicata 9, 1–72 (1980)

    Article  MATH  MathSciNet  Google Scholar 

  34. Tits, J.: Les groupes simples de Suzuki et de Ree. Séminaire Bourbaki 13 (1960/61), No. 210, pp. 18 (1961)

    Google Scholar 

  35. Van Maldeghem, H.: Generalized polygons. Birkhäuser, Basel (1998)

    Book  MATH  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Bart De Bruyn .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2014 Springer India

About this paper

Cite this paper

De Bruyn, B. (2014). The Use of Valuations for Classifying Point-Line Geometries. In: Sastry, N. (eds) Groups of Exceptional Type, Coxeter Groups and Related Geometries. Springer Proceedings in Mathematics & Statistics, vol 82. Springer, New Delhi. https://doi.org/10.1007/978-81-322-1814-2_2

Download citation

Publish with us

Policies and ethics