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// Copyright (C) 1996 The New York Group Theory Cooperative
// See magnus/doc/COPYRIGHT for the full notice.
// Contents: Definition of class GroupFastChecks
//
// Principal Author: Dmitry Bormotov
//
// Status: Usable
//
// Usage: Should contain various fast checks applicable in BE & SM.
//
// Special Notes:
//
// Revision History:
//
#ifndef _GroupFastChecks_h_
#define _GroupFastChecks_h_
#include "FPGroup.h"
// --------------------------- GroupFastChecks ------------------------------ //
class GroupFastChecks {
public:
/////////////////////////////////////////////////////////////////////////
// //
// Constructors: //
// //
/////////////////////////////////////////////////////////////////////////
GroupFastChecks( const FPGroup& G ) :
theGroup( G ),
numOfGens( G.numberOfGenerators() ),
relators( G.getRelators() )
{ }
// Default & copy contructors, operator = provided by compiler.
/////////////////////////////////////////////////////////////////////////
// //
// Accessors: //
// //
/////////////////////////////////////////////////////////////////////////
bool hasTrivialPresentation( ) {
return ( numOfGens == 0 && relators.cardinality() == 0 );
}
// True if the entered presentation has form < ; >.
bool numOfRelsLessNumOfGens( ) {
return ( relators.cardinality() < numOfGens );
}
// True if the number of relators is less than the number of generators.
bool existsGenWithExpSumZeroInEveryRelator( Generator& );
// True if there's such generator exponent sum of which is equal to
// zero in every relator. The generator'll be return as well.
VectorOf<int> getExpSumOfGen( const Generator& g);
// Return exponent sums of g in the group relators.
int GCDOfExpSumOfGen( const Generator& g );
// Return the GCD of exponent sums of g in the group relators.
private:
/////////////////////////////////////////////////////////////////////////
// //
// Data Members: //
// //
/////////////////////////////////////////////////////////////////////////
FPGroup theGroup; // the group to work with
int numOfGens; // number of generators of the group
SetOf<Word> relators; // group relators
};
#endif
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