摘要:

AbstractThe structure and properties of possibleq‐Minkowski spaces are reviewed and the corresponding non‐commutative differential calculi are developed in detail and compared with already existing proposals. This is done by stressing the covariance properties of these algebras with respect to the correspondingq‐deformed Lorentz groups as described by appropriate reflection equations. This allow us to give an unified treatment for differentq‐Minkowski algebras. Some isomorphisms among the space‐time and derivative algebras are demonstrated, and their representations are described briefly. Finally, some, physical consequences and open problems are

ISSN:0015-8208    

DOI:10.1002/prop.2190440102

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe Onsager variation principle is examined from the viewpoint of the thermodynamic analogue of the D'Alembert principle in mechanics when the irreversible processes are linear and thus the system is near equilibrium. The thermodynamic D'Alembert principle is shown to be a precursor to the Onsager variation principle. The thermodynamic D'Alembert principle is then generalised to the cases of nonlinear irreversible processes occurring removed from equilibrium and a generalised form of the Onsager variation principle is obtained under some restricting conditions. The restricted variation principle so deduced has an accompanying exact differential form generalising the Clausius entropy differential (equilibrium Gibbs relations) and contains in it the essence of the thermodynamics of irreversible processes in systems where non‐linear transport processes occur. An example is given for the nonlinear dissipation function in the variation functional. The evolution equations for fluxes are shown to yield those known in the literatur

ISSN:0015-8208    

DOI:10.1002/prop.2190440103

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe study of the projective unitary irreducible representations of the Galilei group (in 1+3 and 1+2 dimensions) is usually done using firstly some group extensions techniques (in this way one is reduced to the study of true unitary representations) and then Mackey induction procedure. In this paper we reobtain these results using a different approach based on the notion of projective systems of imprimitivity due also to Mackey. This extension of the usual Mackey procedure is presented rather extensively and illustrated by detailed computations concerning the classification of the projective unitary irreducible representations.

ISSN:0015-8208    

DOI:10.1002/prop.2190440104

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0015-8208    

DOI:10.1002/prop.2190440101

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY