2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/79068Let $(P\in X,Δ)$ be a three dimensional log canonical pair such that $Δ$ has only standard coefficients and $P$ is a center of log canonical singularities for $(X,Δ)$. Then we get an effective bound of the indices of these pairs and actually determine all the possible indices. Furthermore, under certain assumptions including the log Minimal Model Program, an effective bound is also obtained in dimension $n\geq 4$.25 pagesAlgebraic Geometry14B05; 14E30text