Error-correcting codes over the Mordell-Weil groups of extremal rational elliptic surfaces and the $E_8$ lattice

We construct the $E_8$ lattice from classical error-correcting codes over the Mordell-Weil groups of rational elliptic surfaces that have a singularity lattice of rank 8 (maximal) for all cases of Oguiso-Shioda's classification. By the structure theorem of the Mordell-Weil lattice of rational elliptic surfaces, if the rank of the singularity lattice is maximal, then the Mordell-Weil group is a cyclic group or a direct sum of them. The singularity lattices are glued together by a code over their natural ring to form the $E_8$ lattice. Such constructions of the $E_8$ lattice from codes can be seen as a Lie algebraic extension and further generalization of known code lattice constructions such as Construction A and Construction A${}_{\rm C}$.