6 papers
Generating functions of substitutions
Aisling Pouti, Christopher Ramsey, Nicolae Strungaru
In this paper we study substitutions and some of their associated generating functions. This association takes aperiodicity to transcendence, and vice-versa. These generating funct…
The 1-2-3 conjecture for polygonal tilings
Alison Charlesworth, Christopher Ramsey, Nicolae Strungaru
The 1-2-3 conjecture has been solved positively in 2024 for finite graphs and by extension for infinite graphs which are locally finite. The solution is non-constructive, and findi…
On the spectrum of non-ergodic measures
Michael Francis, Christopher Ramsey, Nicolae Strungaru
Consider a topological dynamical system where the group is abelian and the topologies are locally compact and second-countable. Given an invariant measure for this system, we show…
Diffraction of the primes and other sets of zero density
Adam Humeniuk, Christopher Ramsey, Nicolae Strungaru
In this paper, we show that the diffraction of the primes is absolutely continuous, showing no bright spots (Bragg peaks). We introduce the notion of counting diffraction, extendin…
Crossed products and C*-covers of semi-Dirichlet operator algebras
Adam Humeniuk, Elias G. Katsoulis, Christopher Ramsey
In this paper, we show that the semi-Dirichlet C*-covers of a semi-Dirichlet operator algebra form a complete lattice, establishing that there is a maximal semi-Dirichlet C*-cover.…
Relative position in binary substitutions
Michael Coons, Christopher Ramsey, Nicolae Strungaru
Given an infinite word on a finite alphabet, an immediate question arises:~can we understand the frequency of letters in \,? For words that are the fixed points…