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r""" 

Finite Crystals 

""" 

#***************************************************************************** 

# Copyright (C) 2010 Anne Schilling <anne at math.ucdavis.edu> 

# 

# Distributed under the terms of the GNU General Public License (GPL) 

# http://www.gnu.org/licenses/ 

#****************************************************************************** 

 

from sage.misc.cachefunc import cached_method 

from sage.categories.category_with_axiom import CategoryWithAxiom 

from sage.categories.finite_enumerated_sets import FiniteEnumeratedSets 

from sage.categories.tensor import TensorProductsCategory 

 

class FiniteCrystals(CategoryWithAxiom): 

""" 

The category of finite crystals. 

 

EXAMPLES:: 

 

sage: C = FiniteCrystals() 

sage: C 

Category of finite crystals 

sage: C.super_categories() 

[Category of crystals, Category of finite enumerated sets] 

sage: C.example() 

Highest weight crystal of type A_3 of highest weight omega_1 

 

TESTS:: 

 

sage: TestSuite(C).run() 

sage: B = FiniteCrystals().example() 

sage: TestSuite(B).run(verbose = True) 

running ._test_an_element() . . . pass 

running ._test_cardinality() . . . pass 

running ._test_category() . . . pass 

running ._test_elements() . . . 

Running the test suite of self.an_element() 

running ._test_category() . . . pass 

running ._test_eq() . . . pass 

running ._test_new() . . . pass 

running ._test_not_implemented_methods() . . . pass 

running ._test_pickling() . . . pass 

running ._test_stembridge_local_axioms() . . . pass 

pass 

running ._test_elements_eq_reflexive() . . . pass 

running ._test_elements_eq_symmetric() . . . pass 

running ._test_elements_eq_transitive() . . . pass 

running ._test_elements_neq() . . . pass 

running ._test_enumerated_set_contains() . . . pass 

running ._test_enumerated_set_iter_cardinality() . . . pass 

running ._test_enumerated_set_iter_list() . . . pass 

running ._test_eq() . . . pass 

running ._test_fast_iter() . . . pass 

running ._test_new() . . . pass 

running ._test_not_implemented_methods() . . . pass 

running ._test_pickling() . . . pass 

running ._test_some_elements() . . . pass 

running ._test_stembridge_local_axioms() . . . pass 

""" 

 

@cached_method 

def extra_super_categories(self): 

r""" 

EXAMPLES:: 

 

sage: FiniteCrystals().extra_super_categories() 

[Category of finite enumerated sets] 

""" 

return [FiniteEnumeratedSets()] 

 

def example(self, n = 3): 

""" 

Returns an example of highest weight crystals, as per 

:meth:`Category.example`. 

 

EXAMPLES:: 

 

sage: B = FiniteCrystals().example(); B 

Highest weight crystal of type A_3 of highest weight omega_1 

""" 

from sage.categories.crystals import Crystals 

return Crystals().example(n) 

 

class TensorProducts(TensorProductsCategory): 

""" 

The category of finite crystals constructed by tensor 

product of finite crystals. 

""" 

@cached_method 

def extra_super_categories(self): 

""" 

EXAMPLES:: 

 

sage: FiniteCrystals().TensorProducts().extra_super_categories() 

[Category of finite crystals] 

""" 

return [self.base_category()]