arXiv subjects
Publications and source records attributed to Angel Dimitrov.
We introduce and investigate binary $(k,k)$-designs -- combinatorial structures which are related to binary orthogonal arrays. We derive general linear programming bound and propose as a consequence a universal bound on the minimum possible cardinality of $(k,k)$-designs for fixed $k$ and length $n$. Designs which attain our bound are investigated.
We present the results of a photopolarimetric study of the blazar OJ287 in the period November 2012-January 2015. Observations were conducted using the Focal Reductor FoReRo-2 of the 2-meter RCC telescope of the National Astronomical Observatory (NAO) Rozhen. The observed change of the position angle (P.A.) corresponds to mean rotation of the plane of polarization of 6.23 deg/day, in good agreement with previous measurements. An indication of a correlation between the change of brightness in R-band and the change in the degree of polarization is also observed.