Structure functions of a constraint algebra
= Structure functions of a constraint algebra
{title2=$C_{ij}{}^k(q,p)$}
The coefficients $C_{ij}{}^k(q,p)$ in $\{\varphi_i,\varphi_j\}=C_{ij}{}^k\varphi_k$ are structure functions. A finite real span of <first-class constraints> is a <Lie algebra> when it closes with constant coefficients. General structure functions instead describe closure with phase-space-dependent coefficients, while still permitting <canonical gauge transformations>.