2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/43613An extended Holstein-Primakoff mapping which incorporates both single- and double boson mappings is used in the context of O(N+1) anharmonic oscillator with the global symmetry broken down to O(N) to study the next-to-leading order of the 1/N expansion. It is shown that the Goldstone theorem is obeyed to that order and that the Ward identity is satisfied.24 pages, 3 figuresHigh Energy Physics - Phenomenologytext