It is known that the unknotting number [Formula: see text] of a link [Formula: see text] is less than or equal to half the crossing number [Formula: see text] of [Formula: see text]. We show that there are a planar graph [Formula: see text] and its spatial embedding [Formula: see text] such that the unknotting number [Formula: see text] of [Formula: see text] is greater than half the crossing number [Formula: see text] of [Formula: see text]. We study relations between unknotting number and crossing number of spatial embedding of a planar graph in general.

中文翻译：

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平面图的空间嵌入的解结数和交叉数

已知链接[公式：见文]的解结数[公式：见文]小于或等于[公式：见文]的交叉数[公式：见文]的一半。我们证明有一个平面图[公式：见文]及其空间嵌入[公式：见文]使得[公式：见文]的解结数[公式：见文]大于交叉数的一半[ [公式：见正文]的[公式：见正文]。我们一般研究平面图空间嵌入的解结数和交叉数之间的关系。