高中立体几何课本(甲种本)提到:除简单多面体外,还有不是简单多面体的多面体。例如将正方体挖去一个洞所得到的多面体。(图1)。这里有两个问题值得注意。第一,图1所示几何体是多面体吗? 按同一中学课本上的定义,“由若干个多边形所围成的几何体,叫做多面体。围成多面体的各个多边形叫做多面体的面。”由此,我们得知,多面体的各个面,都必须是平面多边形。现行中学几何课本第一册定义,“由一些线段首尾顺次连结组成的图形,叫做多边形。”按这个定义,图 High School Solid Geometry Textbooks (A kind) mentioned: In addition to simple polyhedrons, there are polyhedrons that are not simple polyhedrons. For example, a polyhedron obtained by digging a square into a hole. (figure 1). There are two issues here that are worth noting. First, is the geometry shown in Figure 1 a polyhedron? According to the definition of the same secondary school textbook, “Geometry enclosed by a number of polygons is called a polyhedron. Each polygon that encloses a polyhedron is called a polyhedral face.” Thus we It is learned that all faces of a polyhedron must be planar polygons. The current Middle School Geometry Textbook Book 1 defines that “graphs that are composed of lines that are connected sequentially from beginning to end are called polygons.” According to this definition,