环圈
数学中的环圈（loop）是拓扑空间X上的连续函数f，其定义域为单位区间I = [0,1]，而且f(0) = f(1)。换句话说，环圈是拓扑学中，起点和终点相同的道路（path）[1]。
环圈也可以视为是从点标空间单位圆S1映射到X的连续映射f，因为S1可以视为是I商空间under the identification of 0 with 1。
X所有环圈的集合可以形成一空间，称为X的环圈空间[1]。
相关条目
[编辑]参考资料
[编辑]- ^ 1.0 1.1 Adams, John Frank, Infinite Loop Spaces, Annals of mathematics studies 90, Princeton University Press: 3, 1978, ISBN 9780691082066.
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