Date of Award

Spring 2023

Document Type

Open Access Dissertation



First Advisor

Ognian Trifonov


This dissertation considers three different topics.

In the first part, we prove that if the least modulus of a distinct covering system is 4, its largest modulus is at least 60; also, if the least modulus is 3, the least common multiple of the moduli is at least 120; finally, if the least modulus is 4, the least common multiple of the moduli is at least 360. The constants 60, 120, and 360 are best possible, they cannot be replaced by larger constants. We also show that there do not exist distinct covering systems with all of the moduli in the interval [n, 9n] for n ≥ 3.

In the second part, we obtain a lower bound for the maximum distance between any three distinct points in an affine lattice which are close to a helix with small curvature and torsion. This is a generalization of analogous results in two dimensions.

In the final part, we prove that every positive integer n which is not equal to 1, 2, 3, 6, 11, 30, 155, or 247 can be represented as a sum of a squarefree number and a prime not exceeding √ n.

Included in

Mathematics Commons