“…for any t ∈ R, 0 < x < 𝑦 or 𝑦 < x < 0, where (t, x) = x𝑓 (t, x) − qF(t, x), F(t, x) = ∫ x 0 𝑓 (t, s)ds. Significantly, Li et al [9] expanded the (MS)-condition for nonlinearity 𝑓 (t, x, 𝑦), that is, there exists a constants G * > 0 such that (t, 𝜁 x, 𝜁𝑦) ≤ (t, x, 𝑦) + G * , (1.4) for any x, 𝑦 ∈ R, 𝜆 > 0 and 0 < 𝜁 ≤ 1, where (t, x, 𝑦) = 𝑓 x (t, x, 𝑦)x + 𝑓 𝑦 (t, x, 𝑦)𝑦−𝜆𝑓 (t, x, 𝑦). In general, the (MS)-condition is crucial in demonstrating that the Palais-Smale sequence or Cerami-sequence is bounded when the nonlinearities that are superlinear do not satisfy the (AR)-condition.…”