What are the fundamental groups of the following spaces?


X3 = {(x; y; z) ∈ R^3 | (x; y; z) ̸= (0; 0; 0)}
X4 = R^3 \ {(x; y; z) | x = 0 , y = 0 , 0 <= z <= 1}
X5 = R^3 \ {(x; y; z) | x = 0 , 0 <= y <= 1}