Central extension of a Lie algebra
= Central extension of a Lie algebra
{title2=$0\to\mathfrak z\to\widehat{\mathfrak g}\to\mathfrak g\to0$}
= Lie algebra central extension
{c}
{synonym}
A central extension is a <Lie algebra> surjection whose <kernel> commutes with every element of the larger algebra. The <Virasoro central extension> adds a central generator to the <Witt algebra>.