Abstract
We study the constrained minimum energy problem with an external field relative to the α-Riesz kernel x−yα−n of order α ∈ (0, n) for a generalized condenser A = (Ai)i∈I in ℝn, n ⩾ 3, whose oppositely charged plates intersect each other over a set of zero capacity. Conditions sufficient for the existence of minimizers are found, and their uniqueness and vague compactness are studied. Conditions obtained are shown to be sharp. We also analyze continuity of the minimizers in the vague and strong topologies when the condenser and the constraint both vary, describe the weighted equilibrium vector potentials, and single out their characteristic properties. Our arguments are based particularly on the simultaneous use of the vague topology and a suitable semimetric structure on a set of vector measures associated with A, and the establishment of completeness theorems for proper semimetric spaces. The results remain valid for the logarithmic kernel on ℝ2 and A with compact Ai, i ∈ I. The study is illustrated by several examples.
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We express our sincere gratitude to the anonymous referee for valuable suggestions, helping us in improving the exposition of the paper.
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The research of the first author was supported, in part, by a Simons Foundation grant no. 282207.
The research of the third and the fourth authors was supported, in part, by the U.S. National Science Foundation under grants DMS-1516400.
The research of the fifth author was supported, in part, by the Scholar-in-Residence program at PUFW and by the Department of Mathematical Sciences of the University of Copenhagen.
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Dragnev, P.D., Fuglede, B., Hardin, D.P. et al. Constrained minimum Riesz energy problems for a condenser with intersecting plates. JAMA 140, 117–159 (2020). https://doi.org/10.1007/s11854-020-0091-x
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DOI: https://doi.org/10.1007/s11854-020-0091-x