J (−△ u+ V′(| u| 2) u) on the real line are invariant under the flow of (∗) in the sense that
there exist random variables X (t) whose laws are ρ (thus independent from t) and such that
t↦ X (t) is a solution to (∗). Besides, for all t, X (t) is almost surely not in L 2 which provides as
a direct consequence the existence of global weak solutions for initial data not in L 2. The
proof uses Prokhorov's theorem, Skorohod's theorem, as in the strategy in [N. Burq, L …