my @sets =
    ([ 0, 1, 2, 3,          7, 8, 9, 10, 11, 12, 13, 14, 15,     ],
     [ 0,       3,          7, 8,    10, 11,     13, 14,     16, ],
     [ 0, 1, 2, 3,    5,    7, 8,    10, 11, 12, 13, 14,     16, ],
     [       2, 3, 4,    6, 7, 8,    10, 11, 12,     14,     16, ],
     [ 0, 1, 2, 3,          7, 8, 9, 10, 11,     13, 14, 15,     ]);


foreach $la (@sets) {
%c= map { $_, $c{$_} += 1; } @$la;
}
foreach $la (sort { $a <=> $b } keys %c) { 
        print "$la is in all sets.\n" if $c{$la} > $#sets; 
}