According to many phenomenological and theoretical studies the distribution of family name frequencies in a population can be asymptotically described by a power law. We show that the Galton–Watson process corresponding to the dynamics of a growing population can be represented in Hilbert...

We discuss some recent determinations of the equation of state for the XY and the Heisenberg universality class.

A center and radius of “perception” (in the sense of environmental cognition) can be formally associated with a written text and operationally defined. Simple algorithms for their computation are presented, and indicators for anisotropy in large scale space perception are introduced. The...

Group invariant expectation values for lattice non-linear vector models [O(N) and CPN−1] in one dimension with a general local action may be expressed as explicit functions of the single-link model expectation values. The value of all these averages at the fixed point of the renormalization...

The general relationship between an arbitrary frequency distribution and the expected value of the frequency distributions of its samples is discussed. A wide set of measurable quantities (“invariant moments”) whose expected value does not in general depend on the size of the sample is...