Department of Mathematics, University of Rijeka, 51 000 Rijeka, Croatia

*e-mail:* `mmaksimovic@math.uniri.hr`

Department of Mathematics, University of Rijeka, 51 000 Rijeka, Croatia

*e-mail:* `sanjar@math.uniri.hr`

**Abstract.** We show that under certain conditions submatrices of orbit
matrices of strongly regular graphs span self-orthogonal codes. In order
to demonstrate this method of construction, we construct self-orthogonal
binary linear codes from orbit matrices of the triangular graphs *T*(2*k*) with
at most 120 vertices. Further, we obtain strongly regular graphs and block
designs from codewords of the constructed codes.

**2010 Mathematics Subject Classification.**
05E30, 20D45, 94B05.

**Key words and phrases.** Strongly regular graph, self-orthogonal code, block design.

DOI: http://doi.org/10.21857/mwo1vczo8y

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