  A mechanism that produces conical dispersion relations is presented. A Kronig
Penney one dimensional array with two different strengths delta function
potentials gives rise to both the gap closure and the dispersion relation
observed in graphene and other materials. The Schr\''odinger eigenvalue problem
is locally invariant under the infinite dimensional Virasoro algebra near
conical dispersion points in reciprocal space, thus suggesting a possible
relation to string theory.
