use FermionicSpaces;
use strict;
use warnings;

my $fs = new FermionicSpaces states => [ 0, 1 ];

my $s1 = $fs->new_space;
my $s2 = $fs->new_space;

my $A = $fs->new_fermion( id => 'A' );
my $B = $fs->new_fermion( id => 'B' );
my $C = $fs->new_fermion( id => 'C' );

$fs->add_fermion_to_space( $A, $s1 );
$fs->add_fermion_to_space( $B, $s1 );
$fs->add_fermion_to_space( $B, $s2 );
$fs->add_fermion_to_space( $C, $s2 );

print "Before:\n", $fs->as_string;

$A->disallow_states(1);

$fs->do_all_possible_exclusions;

print "After:\n", $fs->as_string;