The basic algebraic structure of the Maxwell equations (in a particular form) is first abstracted. This structure is then used as a model for wave equations for other massless particles. Gauge-independent wave equations of Dirac type (more precisely, of Pauli type) are thus found for every half-integral positive spin. Multiple-spin equations of Dirac types are also found. The single-spin equations are then quantized. The infinite-dimensional equations are not considered.

• Received 1 May 1958

DOI:https://doi.org/10.1103/PhysRev.111.1710