“…Equation (1) belongs to a family of models featuring the competition between repulsive (λ 1 ≤ 0)/attractive (λ 1 ≥ 0) and repulsive (λ 2 ≤ 0)/attractive (λ 2 ≥ 0)/terms, that have drawn considerable attention for p = 3 in both the physical and the mathematical communities in recent years (an abridged list of references include [1], [2], [3], [5], [6], [7], [8], [10], [13], [16], [19], [22], [23], [24], [25], [26], [32], [35], [36], [38], [40] and [41]). This combination of nonlinearities in (1) for p > 1 is well-known in optical media (cf.…”