@b = (ab, c);

##</code><code>##

@a = (a, bc, d);

##</code><code>##

sub isOrderedSublist{
    my ( $aref, $bref ) = @_; # references to arrays
    my @a = @$aref; # major - copy so we can safely destroy
    my @b = @$bref; # minor
    my $firstMatched = 0;
    while( not Empty( \@a ) ) {
        if ( $a[0] eq $b[0] ) {
            $firstMatched = 1;
            shift @b;
        else {
            $firstMatched and last;
        }
        shift @a;
    }
    return Empty( \@b ); # success if failure eliminated
}

sub Empty{
    my $aref = shift;
    return( not ( $#$aref + 1 ) );
}