Chapter 4 on the theorema egregium deals with the main contributions by gauss, as developped in his disquisitiones generalis circa super. We have shown theorem i5 that the gauss curvature at a. In this note, we describe a simple way to define the second fundamental form of a hypersur face in rn and use it to prove gausss theorema. The calculations follow more opreahs presentation, but they are valid for completely general coordinates and metrics, i. Gausss theorema egregium latin for remarkable theorem is a foundational result in differential geometry proved by carl friedrich gauss that concerns the. On the evolution of the idea of curvature, from newton to. Download book pdf elementary differential geometry pp 229246 cite as. A property of a surface which depends only on the metric form is an intrinsic property. This worksheet proves gauss theorema egregium via an involved, but straightforward calculation.
The curvature tensor and the theorema egregium 1 1. By this we mean that the converse of the theorem is not true. This is because all normal vectors on the surface will. We have shown theorem i5 that the gauss curvature at a point p is kp lg where l is the second fundamental form and g is. This chapter is a highlight of these lectures, and altogether we shall discuss four di.
S 1 s2 is a local isometry, then the gauss curvature of s1 at p equals the gauss curvature of s2 at fp. Theorem of the day theorema egregium the gaussian curvature of surfaces is preserved by local isometries. Gausss theorema egregium crux sancti patris benedicti. We can at once see that the cylinder, topleft in the illustration, has gaussian curvature k 0 everywhere. We shall use the same theorem to answer above questions. Ib geometry lent 20 proof of gauss theorema egregium let u. Classical differential geometry curves and surfaces in. One of gausss most important discoveries about surfaces is that the gaussian. The theorem can only be used to rule out local isometries between surfaces. The statement is a direct consequence of theorem 2. Curvature and the theorema egregium of gauss deane yang in this note, we describe a simple way to define the second fundamental form of a hypersurface in rn and use it to prove gausss theorema egregium, as well as its analogue in higher dimensions. S1 s2 is a local isometry, then the gauss curvature of s1 at p equals the gauss. The main purpose of this paper is to study the riemannian curvature, derivation formulae and applying it to study the theorema egregium which.
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