Jan 1, 2020
#Alexander trick#collars#Nick Ivanov#Vint Cerf#Haken manifolds#surgery#diffeomorphisms#decomposition#gluing#contractibility#retraction#lens spaces#prism manifolds#elliptic#cyclic group#dihedral group#group theory#Lie groups#SO(3)#O(4)#orthogonal group#isotopy#homotopy#3-torus#SU(2)#tetrahedron#isometry#octahedron#icosahedron#fibrations