“…It is clear that (1.2) admits a unique absolutely continuous solution u ξ (s) = u ξ (s; u) on [0, t], by Proposition A.1, if there exists f ∈ L 1 ([0, t], R) such that |L(ξ(s), u,ξ(s))| f (s), a.e., s ∈ [0, t] . In [5], the authors showed that Proposition 1.1. Let L satisfy conditions (L1)-(L3), then for fixed x, y ∈ R, t > 0 and u ∈ R, the problem (1.3) admits a minimizer.…”