<informationTable xmlns="http://www.sec.gov/edgar/document/thirteenf/informationtable">		<infoTable>
			<nameOfIssuer>ALAMO GROUP INC</nameOfIssuer>
			<titleOfClass>COM</titleOfClass>
			<cusip>011311107</cusip>
			<value>69704</value>
			<shrsOrPrnAmt>
				<sshPrnamt>1700100</sshPrnamt>
				<sshPrnamtType>SH</sshPrnamtType>
			</shrsOrPrnAmt>
			<investmentDiscretion>SOLE</investmentDiscretion>
			<votingAuthority>
				<Sole>1700100</Sole>
				<Shared>0</Shared>
				<None>0</None>
			</votingAuthority>
		</infoTable>
		<infoTable>
			<nameOfIssuer>GENERAL DYNAMICS CORP</nameOfIssuer>
			<titleOfClass>COM</titleOfClass>
			<cusip>369550108</cusip>
			<value>4240514</value>
			<shrsOrPrnAmt>
				<sshPrnamt>33366231</sshPrnamt>
				<sshPrnamtType>SH</sshPrnamtType>
			</shrsOrPrnAmt>
			<investmentDiscretion>SOLE</investmentDiscretion>
			<votingAuthority>
				<Sole>33366231</Sole>
				<Shared>0</Shared>
				<None>0</None>
			</votingAuthority>
		</infoTable>
		<infoTable>
			<nameOfIssuer>PETSMART INC</nameOfIssuer>
			<titleOfClass>COM</titleOfClass>
			<cusip>716768106</cusip>
			<value>625824</value>
			<shrsOrPrnAmt>
				<sshPrnamt>8928862</sshPrnamt>
				<sshPrnamtType>SH</sshPrnamtType>
			</shrsOrPrnAmt>
			<investmentDiscretion>SOLE</investmentDiscretion>
			<votingAuthority>
				<Sole>8928862</Sole>
				<Shared>0</Shared>
				<None>0</None>
			</votingAuthority>
		</infoTable>
</informationTable>
