18 citations · 61 across the 14 of their papers we have counts for
15 papers
Farey Symbols for the Picard Group
Devendra Tiwari, Helena Verrill
We introduce Picard Farey symbols for finite-index subgroups of \(G=\PSL_2(\ZZ[i])\), using the Gaussian Farey tessellation of \(\HH^3\) by ideal octahedra. A symbol records finite…
Hinged Truchet tiling fractals
H Verrill
This article describes a new method of producing space filling fractal dragon curves based on a hinged tiling procedure. The fractals produced can be generated by a simple L-system…
On l-adic representations for a space of noncongruence cuspforms
Jerome W. Hoffman, Ling Long, Helena Verrill
This paper is concerned with a compatible family of 4-dimensional \ell-adic representations ρ_{\ell} of G_\Q:=\Gal(\bar \Q/\Q) attached to the space of weight 3 cuspforms S_3 (Γ) o…
Supercongruences for the Catalan-Larcombe-French numbers
Frazer Jarvis, Helena Verrill
We develop the Stienstra-Beukers theory of supercongruences in the setting of the Catalan-Larcombe-French sequence. We also give some applications to other sequences.
Products of conjugacy classes of the alternating group
Edith Adan-Bante, John Harris, Helena Verrill
Let A_n be the alternating group on n letters. For n>5, we describe the elements alpha, beta in A_n when alpha^{A_n} beta^{A_n} is the union of at most four distinct conjugacy clas…
Lifts of projective congruence groups
Ian Kiming, Matthias Schuett, Helena Verrill
We show that noncongruence subgroups of SL_2(Z) projectively equivalent to congruence subgroups are ubiquitous. More precisely, they always exist if the congruence subgroup in ques…