Subalgebras of the Poincaré algebra AP(2,3) and symmetry reduction of the nonlinear ultrahyperbolic d'Alembert equation. II (Q2638438)

[For part I see ibid. 40, No.4, 351-356 (1988); translation from Ukr. Mat. Zh. 40, No.4, 411-416 (1988; Zbl 0683.35056).] The present paper is the continuation of part I and is dedicated to structure investigation of Poincaré algebras. To an approximation of equivalence the subalgebras lattice of algebra AP(2,2) is described. On the basis of subalgebras lattices of algebras AP(2,3) and AP(2,2) subalgebras invariants are found and symmetric reduction of nonlinear ultrahyperbolic d'Alembert equation is carried out. Two of three references are the authors' papers.