if( $a < $b ) {
    ## Do what is required when $a is the lessor
}
else {
    ## Do what is required when $b is the lessor
}

##</code><code>##

#! perl -slw
use strict;
use X;
use List::Util qw[ min ];

my $a = X->new( .5, .5, .5, 1 );
my $b = X->new( .7, .9, .4, 1 );

print $a < $b ? 'a is the lessor' : 'b is the lessor';
print "\n-------\n";
print min( $b, $a );

__END__
[ 0:38:13.97] c:\test>junk3
a is the lessor

-------

Argument "X=ARRAY(0x1824550)" isn't numeric in subroutine entry at c:\test\junk3.pl line 10.
Argument "X=ARRAY(0x2251a4)" isn't numeric in subroutine entry at c:\test\junk3.pl line 10.
X=ARRAY(0x1824550)