Swerve of a curve

self-rotation of a curve

The part of the variation of the rotation of a curve on an irregular surface not caused by the concentration of the integral curvature of the surface on the set of points of the curve. For a simple arc $ L $, the swerve is equal to $ ( \sigma _ {r} + \sigma _ {l} - \Omega )/2 $, where $ \sigma _ {r} , \sigma _ {l} $ are the variations under right and left traversal of $ L $, while $ \Omega $ is the variation of the curvature of $ L $ as a set. Curves with swerve zero are called quasi-geodesic curves (cf. Quasi-geodesic line).

References

[1]	A.D. Aleksandrov, V.V. Strel'tsov, "Isoperimetric problems and estimates of the length of a curve on a surface" Proc. Steklov Inst. Math. , 76 (1965) pp. 81–99 Trudy Mat. Inst. Steklov. , 76 (1965) pp. 67–80
[a1]	H. Busemann, "Convex surfaces" , Interscience (1958) pp. Chapt. III, Sect. 15