Method for construction of operators in Fock space

It is shown, by providing a general method for the construction that any Fock space linear operator defined on the dense linear manifold spanned by the particle number representation basis can be represented in terms of the annihilation and creation operators. The normal form of the representation is unique.     

Reduction of silicon halides and alkoxides with diisobutylaluminum hydride. Stereochemistry-rate law correlations for the SNiSi and SN2Si mechanisms

Stereochemistry-rate law correlations are given for the reduction of R₃Si*X compounds with i-Bu₂ AlH in either and n-hexane.     

Spin-vibronic transition moments and rotational intensities in doublet-quartet transitions in asymmetric top molecules

Symmetry and time reversal arguments allow the rigorous determination of the nonvanishing and independent spin-vibronic transition moments for doublet-quartet transitions in asymmetric top molecules. Less strict additional relations, leading to a smaller number of independent parameters, are derived by considering an insight of the intensity borrowing mechanism in the case of weak spin-orbit interactions. In this case it is shown that there are either two or three independent transition moments in orthorhombic molecules, depending on the symmetry species of the vibronic wavefunctions involved in the transition.Case (b) selection rules are derived, and it is shown that rotational intensities in orthorhombic molecules can be obtained in all cases by squaring certain sums of either all real or all imaginary terms. A diagrammatical method is devised to identify the form and polarization of the nonvanishing transition moments as well as the symmetry species of the products of those vibronic pairs whose spin-orbit mixing contributes to a given transition moment.     

Looking at a Gaussian process through a window

We show that an observer recording only the presence or absence of a Gaussian process in a window can reconstruct its correlation function.     

Alcune limitazioni per le soluzioni di equazioni paraboliche

Sunto Si discute il problema diCauchy relativo all'equazione del calore, u_t=u_xx, ed a condizioni iniziali sull'asse t. Si provano inoltre alcune proprietà delle soluzioni positive di tale problema e di analoghi problemi diCauchy relativi a più generali equazioni paraboliche.

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Summary We consider theCauchy problem for the heat equation, u_t=u_xx, with initial conditions on the t-axis. We prove some property of positive solutions of this problem, and of similarCauchy problems for more general parabolic equations.

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A Giovanni Sansone nel suo 70^mo compleanno.