6 papers
Envelope of intermediate lines of a plane curve
Ady Cambraia, Mostafa Salarinoghabi, Diego Trindade
For a pair of points in a smooth closed convex planar curve , its mid-line is the line containing its mid-point and the intersection point of the corresponding pair of tangent l…
On Totally umbilical surfaces in the warped product
Ady Cambraia, Abigail Folha, Carlos Peñafiel
In this article we classify the totally umbilical surfaces which are immersed into a wide class of Riemannian manifolds having a structure of warped product, more precisely, we sho…
An additional structure over integer rings
Ady Cambraia, Allan O. Moura, Anderson T. Silva
We present an algebraic structure in modules over integer rings with cardinality prime powers, which allows to define bases. With such structure, we prove a similar version for the…
Envelope of Mid-Hyperplanes of a Hypersurface
Ady Cambraia, Marcos Craizer
Given 2 points of a smooth hypersurface, their mid-hyperplane is the hyperplane passing through their mid-point and the intersection of their tangent spaces. In this paper we study…
On prime factors of Mersenne numbers
Ady Cambraia, Michael P. Knapp, Abílio Lemos +2
Let be the Mersenne sequence defined by . Let be the number of distinct prime divisors of In this short note, we present a description of th…
Envelope of mid-planes of a surface and some classical notions of affine differential geometry
Ady Cambraia Junior, Marcos Craizer
For a pair of points in a smooth locally convex surface in 3-space, its mid-plane is the plane containing its mid-point and the intersection line of the corresponding pair of tange…