Covariant light-cone algebra

By introducing a variable lightlike vector kμ the light-cone gauge algebra of the bosonic string oscillators is rewritten in an apparently covariant form and it is shown that the apparent covariance becomes true covariance if, and only if, the parameters take the usual critical values. In particular it is shown that the k-independence of physical quantities is equivalent to the usual closure of the Lorentz group for fixed kμ and also to the zero-curvature of the light-cone-gauge surface. The connection of the k-formalism with the BRST formalism, and with other aspects of physics, notably spontaneous symmetry breaking mechanisms, is discussed. (orig.)