Principal part of a meromorphic function
= Principal part of a meromorphic function
{wiki=Mittag-Leffler's_theorem#Pole_prescription}
= Principal part
{synonym}
At a point $x$ of a <Riemann surface>, the principal part of a <meromorphic function> is the negative-degree part of its <Laurent series> in a local coordinate. It is equivalently a germ in the quotient $\mathcal K_x/\mathcal O_x$.