A symmetric design is a block design (, , , , ) with the same number of blocks as points, so (or, equivalently, ). An example of a symmetric block design is a projective plane.
Symmetric Block Design
See also
Block Design, Projective PlaneExplore with Wolfram|Alpha
References
Dinitz, J. H. and Stinson, D. R. "A Brief Introduction to Design Theory." Ch. 1 in Contemporary Design Theory: A Collection of Surveys (Ed. J. H. Dinitz and D. R. Stinson). New York: Wiley, pp. 1-12, 1992.Referenced on Wolfram|Alpha
Symmetric Block DesignCite this as:
Weisstein, Eric W. "Symmetric Block Design." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/SymmetricBlockDesign.html