Extensor in Geometric Algebras

This paper, the third in a series of eight introduces some of the basic concepts of the theory of extensors needed for our formulation of the differential geometry of smooth manifolds . Key notions such as the extension and generalization operators of a given linear operator (a (1,1)-extensor) acting on a real vector space V are introduced and studied in details. Also, we introduce the notion of the determinant of a (1,1)-extensor and the concepts of standard and metric Hodge (star) operators, disclosing a non trivial and useful relation between them.