  The Weil correspondence states that the datum of a Seiberg-Witten
differential is equivalent to an algebraic group extension of the integrable
system associated to the Seiberg-Witten geometry. Remarkably this group
extension represents quantum consistent couplings for the $\mathcal{N}=2$ QFT
if and only if the extension is anti-affine in the algebro-geometric sense. The
universal special geometry is the algebraic integrable system whose Lagrangian
fibers are the anti-affine extension groups; it is defined over a base
$\mathscr{B}$ parametrized by the Coulomb coordinates and the couplings. On the
total space of the universal geometry there is a canonical (holomorphic) Euler
differential. The ordinary Seiberg-Witten geometries at fixed couplings are
symplectic quotients of the universal one, and the Seiberg-Witten differential
arises as the reduction of the Euler one in accordance with the Weil
correspondence. This universal viewpoint allows to study geometrically the
flavor symmetry of the $\mathcal{N}=2$ SCFT in terms of the Mordell-Weil
lattice (with N\'eron-Tate height) of the Albanese variety $A_\mathbb{L}$ of
the universal geometry seen as a quasi-Abelian variety $Y_\mathbb{L}$ defined
over the function field $\mathbb{L}\equiv\mathbb{C}(\mathscr{B})$.
