Contributions to a general theory of view-obstruction problems. II (Q1924257)

[For Part I, see Can. J. Math. 45, 517-536 (1993; Zbl 0794.11026).] The authors develop a theory of view-obstruction problems. In these problems, congruent copies of a centrally symmetric convex body \(C\) centered at \(({1\over2},\dots, {1\over2})+\mathbb{Z}^n\) are uniformly expanded until they block all rays (or subspaces) from the origin into the open positive cone. If \(C\) is the cube, these problems are closely related to diophantine approximation, and problems of this type were first proved in 1967 [the reviewer, Monatsh. Math. 71, 263-269 (1967; Zbl 0148.27505)] long before Schoenberg's billiard problem of 1975. Here the authors generalize view-obstruction problems for rays to arbitrary flats.