  The biduality and reflexivity theorems are known to hold for projective
varieties defined over fields of characteristic zero, and to fail in positive
characteristic. In this article, we construct a notion of reflexivity and
biduality in positive characteristic by generalizing the ordinary tangent space
to the notion of $h$-tangent spaces. The ordinary reflexivity theory can be
recovered as the special case $h=0$, of our theory.
  Several varieties that are not ordinary reflexive or bidual become reflexive
in our extended theory.
