  F. V. Gubarev et al. (``On the significance of the vector potential
squared'', Phys. Rev. Lett. 86, 2220) have argued that the vector potential
itself may have physical meaning, in defiance of the gauge equivalence
principle. Earlier R. I. Khrapko proposed a gauge noninvariant electrodynamics
spin tensor (``Spin density of electromagnetic waves''). The standard
electrodynamics spin tensor is zero.
  Here we point out that the Biot-Savarat formula uniquely results in a
preferred, "true" vector potential field which is generated from a given
magnetic field. A similar integral formula uniquely permits to find a "true"
scalar potential field generated from a given electric field even in the case
of a nonpotential electric field.
  A conception of differential forms is used. We say that an exterior
derivative of a form is the boundary of this form and the integration of a form
by the Biot-Savarat-type formula results in a new form named the generation.
Generating from a generation yields zero. The boundary of a boundary is zero. A
boundary is closed. A generation is sterile. A conjugation is considered. The
conjugation converts closed forms to sterile forms and back. It permits to
construct chains of forms. The conjunction differs from the Hodge star
operation: the conjugation does not imply the dualization. A circularly
polarized wave is considered in view of the electrodynamics spin tensor
problem.
  A new anthropic principle is presented.
