<?xml version="1.0" encoding="UTF-8"?>

<record version="8" id="1098">
 <title>Riemann-Roch theorem for curves</title>
 <name>RiemannRochTheorem</name>
 <created>2001-12-12 17:31:45</created>
 <modified>2006-02-21 12:52:24</modified>
 <type>Theorem</type>
 <creator id="2727" name="mathcam"/>
 <author id="2727" name="mathcam"/>
 <author id="62" name="nerdy2"/>
 <classification>
	<category scheme="msc" code="14H99"/>
	<category scheme="msc" code="19L10"/>
 </classification>
 <related>
	<object name="HurwitzGenusFormula"/>
 </related>
 <preamble>\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{graphicx}
\usepackage{xypic}</preamble>
 <content>Let $C$ be a projective nonsingular curve over an algebraically closed field.  If $D$ is a divisor on $C$, then

$$\ell(D) - \ell(K-D) = {\rm deg}(D) + 1 - g$$

where $g$ is the genus of the curve, and $K$ is the canonical divisor ($\ell(K)=g$).  Here $\ell(D)$ denotes the dimension of the \PMlinkid{space of functions associated to a divisor}{SpaceOfFunctionsAssociatedToADivisor}.</content>
</record>
