Displaying similar documents to “Heights in finite projective space, and a problem on directed graphs.”

Symmetry of iteration graphs

Walter Carlip, Martina Mincheva (2008)

Czechoslovak Mathematical Journal

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We examine iteration graphs of the squaring function on the rings ℤ / n ℤ when n = 2 k p , for p a Fermat prime. We describe several invariants associated to these graphs and use them to prove that the graphs are not symmetric when k = 3 and when k ≥ 5 and are symmetric when k = 4 .

On the Domination of Cartesian Product of Directed Cycles: Results for Certain Equivalence Classes of Lengths

Michel Mollard (2013)

Discussiones Mathematicae Graph Theory

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Let (−→ Cm2−→ Cn) be the domination number of the Cartesian product of directed cycles −→ Cm and −→ Cn for m, n ≥ 2. Shaheen [13] and Liu et al. ([11], [12]) determined the value of (−→ Cm2−→ Cn) when m ≤ 6 and [12] when both m and n ≡ 0(mod 3). In this article we give, in general, the value of (−→ Cm2−→ Cn) when m ≡ 2(mod 3) and improve the known lower bounds for most of the remaining cases. We also disprove the conjectured formula for the case m ≡ 0(mod 3) appearing in [12]. ...

On Obláth's problem.

Gica, Alexandru, Panaitopol, Laurenţiu (2003)

Journal of Integer Sequences [electronic only]

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On the basic character of residue classes.

Peter J. Hilton, Jennifer Hooper, Jean Pedersen (1989)

Publicacions Matemàtiques

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Let t, b be mutually prime positive integers. We say that the residue class t mod b is basic if there exists n such that t ≡ -1 mod b; otherwise t is not basic. In this paper we relate the basic character of t mod b to the quadratic character of t modulo the prime factors of b. If all prime factors p of b satisfy p ≡ 3 mod 4, then t is basic mod b if t is a quadratic non-residue mod p for all such p; and t is not basic mod b if t is a quadratic residue mod p for all such p. If, for all...