The universal cover of the double doughnut is a hyperbolic space, where we only shrink the xy plane, but not the height
Аналитик Брайант, на мнение которого ссылается издание, заявил, что наиболее вероятным объяснением является «ошибочная идентификация» школы — якобы силы атаковали объект, не осознавая, что внутри может находиться большое количество гражданских лиц.，这一点在PDF资料中也有详细论述
Friedmann, still a minor, became a ward of the State of Tennessee. Lawyers at Davidson County’s juvenile court found the presence of this bright, courteous young man puzzling. He began attending the Tennessee Preparatory School, a state-run residential school for delinquent and neglected children, which had a forbidding reputation. Administrators shaved the heads of boys who tried to run away. Before Friedmann arrived, two students killed themselves. A student sued the school, alleging that he was being kept there against his will, and the Tennessean reported that it was run “like a correctional institution.”，详情可参考PDF资料
onlinelibrary.wiley.com，更多细节参见电影