Is this what you meant? Taken literally, $a has a defined value, and the tertiary operator is unnecessary, so I presume you are looking for a default value kind of operation. 

$a = 'text';
$b = $a || '';

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Your third example is not reducible. At least, not by me.

In reply to Re: check for existing value, else set to default by pbeckingham
in thread check for existing value, else set to default by nmerriweather

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