  Starting from generic bilinear Hamiltonians, constructed by covariant vector,
bivector or tensor fields, it is possible to derive a general symplectic
structure which leads to holonomic and anholonomic formulations of Hamilton
equations of motion directly related to a hydrodynamic picture. This feature is
gauge free and it seems a deep link common to all interactions,
electromagnetism and gravity included. This scheme could lead toward a full
canonical quantization.
