In this paper, it is proved that, if a toric ideal possesses a fundamental binomial none of whose monomials is squarefree, then the corresponding semigroup ring is not very ample. Moreover, very ample semigroup rings of Lawrence type are discussed. As an application, we study very ampleness of configurations arising from contingency tables.

Statistical matching (sometimes called data fusion, synthetical matching) aims at combining information available in distinct sample surveys referred to the same target population. Formally, let Y and Z be two random variables; statistical matching aims at estimating the joint (Y, Z) distribution function (e.g. a contingency table or a regression coefficient) or some of its parameters when: (i)...

Let s, t,m, n be positive integers such that sm = tn. Let M(m, s;n, t) be the number of m × n matrices over {0, 1, 2, . . . } with each row summing to s and each column summing to t. Equivalently, M(m, s;n, t) counts 2-way contingency tables of order m× n such that the row marginal sums are all s and the column marginal sums are all t. A third equivalent description is that M(m, s;n, t) is the ...

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We should not have to look at the entire corpus (e.g., the Web) to know if two words are associated or not.1 A powerful sampling technique called Sketches was originally introduced to remove duplicate Web pages. We generalize sketches to estimate contingency tables and associations, using a maximum likelihood estimator to find the most likely contingency table given the sample, the margins (doc...

The statistical analysis of the heterogeneity of the style of a text often leads to the analysis of contingency tables of ordered rows. When multiple authorship is suspected, one can explore that heterogeneity through either a change-point analysis of these rows, consistent with sudden changes of author, or a cluster analysis of them, consistent with authors contributing exchangeably, without t...