This (free) educational project has been created by Laurin Gschnitzer (15 years of age).
MathematicsTopology

Gauss–Bonnet Theorem

∫_M K dA + ∮_∂M kg ds = 2π χ

Links the curvature of a surface to its topology through the Euler characteristic.

More detailed explanations, examples and illustrations for this entry are coming soon.