#  Copyright (c) 1997-2015
#  Ewgenij Gawrilow, Michael Joswig (Technische Universitaet Berlin, Germany)
#  http://www.polymake.org
#
#  This program is free software; you can redistribute it and/or modify it
#  under the terms of the GNU General Public License as published by the
#  Free Software Foundation; either version 2, or (at your option) any
#  later version: http://www.gnu.org/licenses/gpl.txt.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#-------------------------------------------------------------------------------

object ValuatedMatroid {

  ### PROPERTIES ###


  # @category Valuation
  # Defines a valuation on each basis. Entry number i is a valuation on 
  # the i-th element of [[BASES]]. Must fulfill the tropical Plücker relations.
  property VALUATION_ON_BASES : Vector<TropicalNumber<Addition,Scalar>> {
    sub canonical { &canonicalize_tropical_rays; }
  };
  
  # @category Valuation
  # Defines a valuation on each circuit. Row i is a representative of 
  # the i-th element of [[CIRCUITS]]. Must fulfill the tropical circuit
  # valuation axioms. The representative is normalized such that the first
  # non-tropical-zero entry is 0.
  property VALUATION_ON_CIRCUITS : Matrix<TropicalNumber<Addition,Scalar>> {
    sub canonical { &canonicalize_tropical_rays; }
  };

  # @category Combinatorics 
  # This is the matroid subdivision of [[POLYTOPE]] according to the lifting defined by 
  # [[VALUATION_ON_BASES]] (or minus [[VALUATION_ON_BASES]] in the case of max).
  property SUBDIVISION : Array<Set<Int>> {
      sub equal {
          defined(eval { find_permutation(@_) })
      }
  }
 
  ### RULES ###
  
  rule VALUATION_ON_BASES : N_ELEMENTS, BASES, CIRCUITS, VALUATION_ON_CIRCUITS {
    valuated_bases_from_circuits($this);
  }
  
  rule VALUATION_ON_CIRCUITS  : N_ELEMENTS, BASES, CIRCUITS, VALUATION_ON_BASES {
    valuated_circuits_from_bases($this);
  }
  
  rule CIRCUITS, N_ELEMENTS : VALUATION_ON_CIRCUITS {
    circuits_supports($this);
  }
  
  rule SUBDIVISION : POLYTOPE, VALUATION_ON_BASES {
      my $v = Addition->orientation * (new Vector<Scalar>($this->VALUATION_ON_BASES));
      $this->SUBDIVISION = polytope::regular_subdivision($this->POLYTOPE->VERTICES, $v);
  }
  
}

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