Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2023/ii/paper-2/26g/d/solution

No. For sufficiently smooth curves,
is unchanged by proper Euclidean motions and transforms correctly under translations of the arc-length parameter, so it is a pointwise Euclidean invariant of a curve. It is not determined by the two numbers and .
For a concrete comparison near , use the plane curve reconstructed from curvature construction with
The resulting unit-speed planar curves both have and , but their curvature derivatives at zero are respectively and . Thus no single function can satisfy for all curves.
Indeed, the covariance conditions alone even permit nonlocal examples such as . This is the distinction recorded by pointwise Euclidean invariants need not depend only on current curvature and torsion.

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