Abstract
Using Brouwer degree and convex analysis, we obtain geometric conditions for the existence of solutions of multipoint boundary value problems for n-dimensional difference systems of the form
when T is a positive integer, the vector fields f(k, u) point outside a bounded convex set of on its boundary, and the diagonal matrix function g(k) satisfies suitable conditions, which cover the periodic boundary conditions.
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Notes
No potential conflict of interest was reported by the author.
To André Vanderbauwhede, a friend of forty years.