# Math Help - polynomials direct and inverse image

1. ## polynomials direct and inverse image

Show that the subset X of polynominals in R2n[X] all of whose odd coefficients a2i+1 are zero forms a subspace of R2n[X]. Describe D-->(X) and D<--(X).
Do D-->(X) mean the set of polynomials whose even coefficients are zero, and D<--(X) mean the set of polynomials whose odd coefficients are zero?