False in Perl is "", 0, undef. So 
$scalar eq ""    => (implies)   !$scalar

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but 
!$scalar      => (implies) one of: ($scalar eq "") 
                                   ($scalar == 0)
                                   (defined $scalar eq "")

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but that can't be transformed naïvely to a conjunction (with or or ||) without warnings for some values.

In reply to Re: differences between eq "" and ! by ferreira
in thread differences between eq "" and ! by Anonymous Monk

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