A method of constructing second-quantization formalism on a set of orthonormal geminals (two-particle antisymmetric functions) is described. Instead of using an initial set of creation and annihilation operators with nontrivial commutation rules, the so-. -called ideal creation and annihilation operators, satisfying elementary Bose commutation rules, are used. The resulting Hamiltonian and an a...

This work is an attempt of generalization of the simple statement about the requirements of commutation of words for the case of languages. In the paper, the necessary condition for commutation of languages are obtained, and in the prefix case the necessary and sufficient conditions are obtained. It is important to note that the considered alphabets and languages can be infinite. The possibilit...

We show that the infinite imaginary anomalous dimensions of certain heavy quark-antiquark currents in the HQET arise due to an inappropriate commutation of two limits, namely coinciding velocities and infinite cutoff. This commutation is not apparent when dimensional regularization is used, but it can be made manifest in a cutoff regularization. We argue that operators containing heavy quark an...

We prove some commutation relations for a 3-graded Lie algebra, i.e., a Z-graded Lie algebra whose nonzero homogeneous elements have degrees −1, 0 or 1, over a field K. In particular, we examine the free 3-graded Lie algebra generated by an element of degree −1 and another of degree 1. We show that if K has characteristic zero, such a Lie algebra can be realized as a Lie algebra of matrices ove...

The present work is concerned with the development of commutative discrete filters for unstructured grids and contains two main contributions. First, building on the work of Marsden et al. [J. Comp. Phys. 175 (2002) 584], a new commutative discrete filter based on least-squares techniques is constructed. Second, a new analysis of the discrete commutation error is carried out. The analysis indic...