ド・モルガンの法則

$\displaystyle \sim (x \land y)$	$\textstyle =$	$\displaystyle \sim x \lor \sim y$	(59)
$\displaystyle \sim (x \cdot y)$	$\textstyle =$	$\displaystyle \sim x \lor \sim y$	(60)
$\displaystyle \sim (xy)$	$\textstyle =$	$\displaystyle \sim x \lor \sim y$	(61)
$\displaystyle \sim (x \lor y)$	$\textstyle =$	$\displaystyle \sim x \land \sim y$	(62)
$\displaystyle \sim (x \lor y)$	$\textstyle =$	$\displaystyle \sim x \cdot \sim y$	(63)
$\displaystyle \sim (x \lor y)$	$\textstyle =$	$\displaystyle \sim x \sim y$	(64)