Editing Winding number (section)

=== Space curves ===
Turning number cannot be defined for space curves as [[Degree of a continuous mapping|degree]] requires matching dimensions. However, for [[locally convex]], closed [[space curve]]s, one can define '''tangent turning sign''' as <math>(-1)^d</math>, where <math>d</math> is the turning number of the [[stereographic projection]] of its [[tangent indicatrix]]. Its two values correspond to the two [[regular homotopy#non-degenerate homotopy|non-degenerate homotopy]] classes of [[locally convex]] curves.<ref>{{Cite journal|last=Feldman|first=E. A.|date=1968|title=Deformations of closed space curves|journal=Journal of Differential Geometry|language=en|volume=2|issue=1|pages=67–75|doi=10.4310/jdg/1214501138 |s2cid=116999463 |doi-access=free}}</ref><ref>{{Cite journal|last1=Minarčík|first1=Jiří|last2=Beneš|first2=Michal|date=2022|title=Nondegenerate homotopy and geometric flows|journal=Homology, Homotopy and Applications|language=en|volume=24|issue=2|pages=255–264|doi=10.4310/HHA.2022.v24.n2.a12 |s2cid=252274622 |url=https://qmro.qmul.ac.uk/xmlui/handle/123456789/79678 |arxiv=1807.01540}}</ref>