  Let $M$ be a T-motive. We introduce the notion of duality for $M$. Main
results of the paper (we consider uniformizable $M$ over $F_q[T]$ of rank $r$,
dimension $n$, whose nilpotent operator $N$ is 0):
  1. Algebraic duality implies analytic duality (Theorem 5). Explicitly, this
means that the lattice of the dual of $M$ is the dual of the lattice of $M$,
i.e. the transposed of a Siegel matrix of $M$ is a Siegel matrix of the dual of
$M$.
  2. Let $n=r-1$. There is a 1 -- 1 correspondence between pure T-motives (all
they are uniformizable), and lattices of rank $r$ in $C^n$ having dual
(Corollary 8.4).
