In this paper, we introduce a study of prolongations of representations of Lie groups. We obtain a faithful (one-to-one) representation of TG where G is a finite-dimensional Lie group and TG is the tangent bundle of G, by using (not necessarily faithful) representations of G. We show that tangent functions of Lie group actions correspond to prolonged representations. We prove that if two representations are equivalent, then their prolongations are equivalent too. We show that if U is an invariant subspace for a representation, then TU is an invariant subspace for the prolongation of the given representation and vice versa. We prove that if the prolongation of ��is an irreducible representation, then ��is also an irreducible representation. Finally we show that prolongations of direct sum of two representations are direct sum of their prolongations.

13 pages