ABSTRACT

DEFINITION 6 .1 .3 . W e say that / G O M i f / € C ° ° ( R n ) and for each a e Nn there exist M > 0 and k G N such that

—f{x) <M{l + \x\2)k.

REMARK 6 . 1 . 1 . It is easy to check that i f ip G S and / G OM, then fip is i n S . Moreover , i f ipv G S and ipv converges to ip i n «S, then fipu converges to f(p i n S. T h i s statement shows us that i f / is i n O M and T is i n <S', then fT is also i n S' (see Sect ion 1 . 7 ) .