3 ms·
Hairy bagels, on the other hand, can be combed without cowlicks.
by nealabq 14y ago
Hairy bagels, on the other hand, can be combed without cowlicks.
- Devilboy 14y agoWhat about a bagel with two holes?
- sbi 14y agoThe Euler characteristic of a compact orientable genus g surface X is nonzero if g is not 1 (the general formula is 2-2g), so the Euler class e(TX) of the tangent bundle TX of X is nonzero. This implies that TX cannot have a continuous nowhere-vanishing section. If it did, e(TX) would be 0. The single-holed torus is the only orientable compact surface that possesses a continuous nonvanishing vector field.