Fourier-Type Minimal Extensions in Real $L_1$-Space

Discrete integer Fourier transform in real space: elliptic Fourier transform

Hyperbolic surfaces of $L_1$-2-type

In this paper, we show that an $L_1$-2-type surface in the three-dimensional hyperbolic space $H^3subset R^4_1$ either is an open piece of a standard Riemannian product $ H^1(-sqrt{1+r^2})times S^{1}(r)$, or it has non constant mean curvature, non constant Gaussian curvature, and non constant principal curvatures.

Minimal Duval Extensions

A word v = wu is a (nontrivial) Duval extension of the unbordered word w, if (u is not a prefix of v and) w is an unbordered factor of v of maximum length. After a short survey of the research topic related to Duval extensions, we show that, if wu is a minimal Duval extension, then u is a factor of w. We also show that finite, unbordered factors of Sturmian words are Lyndon words.

Reconstruction in Fourier space

We present a fast iterative FFT-based reconstruction algorithm that allows for nonparallel redshift-space distortions (RSD). We test our algorithm on both N-body dark matter simulations and mock distributions of galaxies designed to replicate galaxy survey conditions. We compare solenoidal and irrotational components of the redshift distortion and show that an approximation of this distortion l...

Minimal extensions of Pi01 classes

A minimal extension of a Π1 class P is a Π 0 1 class Q such that P ⊂ Q, Q − P is infinite, and for any Π1 class R, if P ⊂ R ⊂ Q, then either R −P is finite or Q−R is finite; Q is a nontrivial minimal extension of P if in addition P and Q have the same Cantor-Bendixson derivative. We show that for any class P which has a single limit point A, and that point of degree ≤ 0′, P admits a nontrivial ...