It is the aim of the present work to prove, under appropriate conditio
ns, lower estimates for the dimension of Ow1 + ... + Qw(m) over Q, whe
re w1, ..., w(m) are given real numbers. In particular, if this dimens
ion is m, i.e. if w1, ..., w(m) are linearly independent over Q, we ar
e also interested in a quantitative version of this fact. Our qualitat
ive theorems generalize a result of Nesterenko. Its formulation is qui
te similar to the ''axiomatization'' of methods for algebraic independ
ence, as it became usual during the last decade.