public static function PDF($x, $μ, $σ)
{
Support::checkLimits(self::LIMITS, ['x' => $x, 'μ' => $μ, 'σ' => $σ]);
$π = \M_PI;
$xσ√2π = $x * $σ * sqrt(2 * $π);
$⟮ln x − μ⟯² = pow(log($x) - $μ, 2);
$σ² = $σ ** 2;
return 1 / $xσ√2π * exp(-($⟮ln x − μ⟯² / (2 * $σ²)));
}