A topological space \(X\) is semilocally simply connected if every \(x\in X\) has a neighborhood \(U\) such that the homomorphism \(\pi_1(U, x)\to\pi_1(X, x)\) of fundamental groups induced by the inclusion \(U\hookrightarrow X\) is trivial.
[@Hat02].
What does it mean for a space to be semilocally simply connected?