“…Optimization problems for Schrödinger operators (for k = 1, 2 the result was proved in [34], while for generic k ∈ N the existence is proved in [26]) min λ k (− +V ) : V : R d →[0, +∞] measurable, Optimization problems for Schrödinger operators (for k = 1, 2 the result was proved in [34], while for generic k ∈ N the existence is proved in [26]) min λ k (− +V ) : V : R d →[0, +∞] measurable,…”