ABSTRACT = Rank-based sampling (RBS) designs are alternatives to simple random sampling that can sometimes offer large improvements in precision for estimating population parameters such as the mean, quantiles, etc. The original idea was proposed in connection with estimating the mean pasture and forage yields in a paper by McIntyre (1952).
Rank-based sampling designs for environmental and ecological studies with an application in fisheries
ABSTRACT = A classical result states that the very general surface of degree d larger than three in P3 has Picard number 1, and that the locus of surfaces of degree d with Picard number greater than 1 has codimension at least d-3.
Moreover, the lower bound is reached by the families of surfaces which contain a line. In this talk I will show how, under suitable assumptions, this can be generalized to surfaces in (normal) projective simplicial toric 3-folds.
Joint work with Antonella Grassi.
The Noether-Lefschetz locus of surfaces in toric 3-folds
Josel Cioppa (N/A)
A well known method for calculating polynomial integrals over the classical matrix groups and their quantum analogues, due to B. Collins and P. Sniady, is known as Weingarten calculus. In this talk, we will discuss an alternative method which, while similar in spirit to Weingarten calculus, allows for closed formulas for integrating over the first k rows of a matrix group (for k less than the size of the group). Cheers,
A new approach to integration over the Unitary and Orthogonal groups, as well as their quantum analogues.
ABSTRACT:The famous Bruck-Ryser-Chowla theorem gives necessary conditions for the existence of symmetric designs. Here we present an adaptation of this famous theorem on the existence of symmetric pair coverings which have a 2-regular excess. In particular, we apply the Hasse-Minkowski invariant of rationally congruent matrices to study possible cycle types in the excess. Joint work with Sarada Herke and Daniel Horsley
Some non-existence results for symmetric coverings with 2-regular excess
Brice Rodrigue Mbombo (University of São Paulo)
We will present several Ramsey properties for matrices and some applications, including the extreme amenability of the group of isometries of the Gurarij space and an alternative proof of the Graham-Leeb-Rothschild theorem on Grassmannians over a finite field. This is a joint work with Dana Bartošová (University of São Paulo) and Jordi López-Abad (ICMAT Madrid).