Il Club dei Volterriani: Il Volterriano Nr.7, 1999

Ilse Walker
The necklace principle of coding: Patterns of forces in relation to informational determinism
(Abstract. It is argued that specific combinations of zero force and of specific forces between the parts of complex structures and processes result in biological organization, characterized by repetition of unpredictable, complex structures and functions. Death, variation and the necessity of copy-reproduction, i.e. of selection, are consequences of these systemic patterns of force vectors.)

Antonio Steiner, Fabrizio Pini, Martin J. Gander
Selezione e convivenza in sistemi darwiniani
(Abstract. Natural selection in darwinian systems with diagonal linear part leads to the extinction of all species except one. We analyze a two population problem with general linear part and identify the cases which permit coexistence. Then we generalize the results to higher dimensional problems with either cyclic or quasicyclic structure. To obtain analytical solutions we use Eigen's method of quasi-species. )

Antonio Steiner, Martin J. Gander
Parametrische Lösungen der Räuber-Beute-Gleichungen im Vergleich
(Abstract. Solutions of prey-predator-systems are closed orbits. Applying a classical numerical method to compute the solution however, one obtains spiraling solutions which are either converging to the steady state or diverging to infinity. We propose three numerical methods which reproduce the closed orbits exactly and thus contain numerical error only in the time component of the solution.)

Orfeo Mazzella, Federica Marone
A 2D Self-Affine Asperity Model for Earthquake Statistics
(Abstract. We show that a mathematical model based on fractal fault geometry instead of redistributing local interactions can produce statistics of time and place of earthquake occurence that cannot be discriminated from statistics produced by a SOC model or by a statistical study of empirical earthquakes.)

Marco Geri, Davide Ferrari
Equazioni differenziali lineari del secondo ordine
(Abstract. After the introduction of the solution of the second order linear differential equation, some application from the classical physics and from the sociology are showed.)

Luca Gambazzi, Elias Vicari
Equazioni differenziali non lineari del secondo ordine
(Abstract. Some examples of mathematical modelling are analysed with the use of non--linear differential equations: the planetary motion and some pursuit curves.)