The realisations of all classes of unitary irreducible representations of the generalised Poincare group P(1,4) have been found in a basis in which the Casimir operators of its important subgroup,… Expand

We present a survey of results regarding the investigation of the conditions of the symmetry of nonlinear equations of mathematical and theoretical physics: the wave equation, the Schrödinger,… Expand

In the present paper, we solve the problem of separation of variables in the wave equationutt−uxx+V(x)u=0 and give a complete classification of potentialsV(x) forwhich equations of this type admit… Expand

Invariants of the maximal rank-3 and rank-4 subalgebras of the Poincaré algebras AP(2,2), which is the maximal invariance algebra of the d'Alembert equation □u+λuk=0,k=1, and the Liouville equation… Expand