The Question of the Exact Value of One-Sided Width Remains Open

摘要

In Sec. 10.4 of Chap. 10 of the book, one-sided widths of the periodic classes W~r_∞, are considered. However, the main (according to the authors of the book) statement of that section, Lemma 10.4.1 on p. 230, is false. This lemma is given without proof in the book. It is due to Ruban, but in, the proof is given only schematically; it is based on constructing a special map and calculating its degree.