Regular first-class phase-space reduction
= Regular first-class phase-space reduction
{title2=$\dim\Gamma_{\mathrm{phys}}=2N-2n$}
For $n$ independent regular <first-class constraints> in a $2N$-dimensional phase space, imposing the equations removes $n$ dimensions and quotienting independent gauge orbits removes another $n$. Reducibility, singular strata or vanishing gauge directions can invalidate that elementary count. Closure of the <constraint algebra> is necessary but does not by itself establish regularity.