【摘要】 一个不可定向地图,如果只有一个顶点和一个面,则称它为一个魔.对于一类特殊的魔,称为简魔,论证了棱数不同的简魔不可能初等等价,任何一个不可定向地图都与某个简魔初等等价.用简魔确定了不可定向地图的初等等价类.更多还原

【Abstract】 A nonorientable map with one vertex and one face is called a barfly.For a type of special barflies,said to be simplified,it is shown that two simplified barflies of different sizes are not basic equivalent and that any nonorientable map is basic equivalent to one of the simplified barflies.Hence,nonorientable maps are classified by the basic equivalence into simplified barflies. AMS classification:05C10,05C30,11B85,14J10更多还原