ADVANCES IN APPLIED CLIFFORD ALGEBRAS, cilt.27, ss.2333-2343, 2017 (SCI İndekslerine Giren Dergi)
Clifford algebras are used in theoretical physics and in particular, in the general theory of relativity, where Einstein's equations are rewritten in Girard (Adv Appl Clifford Algebras 9(2):225-230, 1999) within a Clifford algebra. Let M be a manifold with a torsion-free connection which induces on its cotangent bundle T* M , a semi-Riemannian metric (g) over bar , called the natural Riemann extension, Kowalski and Sekizawa (Publ Math Debrecen 78:709-721, 2011). The main result of the present paper gives a necessary and sufficient condition for (g) over bar restricted to certain hypersurfaces of T* M to be Einstein.