MathML generated by MathToWeb
A MathML example displaying the AMS-Latex pairing delimiters \lvert and \rvert.
The commands \left and \right instruct Latex and MathToWeb to automatically size the delimiters to properly encompass whatever expression they enclose.

$\left|\genfrac{}{}{0.1ex}{}{f(x+{\delta }_m)-f\left(x\right)}{{\delta }_m}\right|\ge \zeta$ $\left\lvert \frac{f(x+\delta_m) - f(x)}{\delta_m} \right\rvert \ge \zeta$

<math xmlns="http://www.w3.org/1998/Math/MathML">
<mrow>
	<mo>&verbar;</mo>
	<mfrac linethickness="1">
		<mrow>
			<mi>f</mi>
			<mrow>
				<mo maxsize="1.00 em">(</mo>
				<mi>x</mi>
				<mo>+</mo>
				<msub>
					<mi>&delta;</mi>
					<mi>m</mi>
				</msub>
				<mo maxsize="1.00 em">)</mo>
			</mrow>
			<mo>-</mo>
			<mi>f</mi>
			<mrow>
				<mo maxsize="1.00 em">(</mo>
				<mi>x</mi>
				<mo maxsize="1.00 em">)</mo>
			</mrow>
		</mrow>
		<mrow>
			<msub>
				<mi>&delta;</mi>
				<mi>m</mi>
			</msub>
		</mrow>
	</mfrac>
	<mo>&verbar;</mo>
	<mo>&ge;</mo>
	<mi>&zeta;</mi>
</mrow>
</math>