example of a semilocally simply connected space which is not locally simply connected


Let H⁢R be the Hawaiian rings, and define X to be the cone over H⁢R. Then, X is connectedPlanetmathPlanetmath, locally connected, and semilocally simply connected, but not locally simply connected.

Too see this, let p∈H⁢R be the point to which the circles converge in H⁢R, and represent X as H⁢R×[0,1]/H⁢R×{0}. Then, every small enough neighborhoodMathworldPlanetmathPlanetmath of q:=(p,1)∈X fails to be simply connected. However, since X is a cone, it is contractible, so all loops (in particular, loops in a neighborhood of q) can be contracted to a point within X.

Title example of a semilocally simply connected space which is not locally simply connected
Canonical name ExampleOfASemilocallySimplyConnectedSpaceWhichIsNotLocallySimplyConnected
Date of creation 2013-03-22 13:25:15
Last modified on 2013-03-22 13:25:15
Owner antonio (1116)
Last modified by antonio (1116)
Numerical id 5
Author antonio (1116)
Entry type Example
Classification msc 54D05
Classification msc 57M10