#NEWLINE# def _simplify( self ) : #NEWLINE# #INDENT# 'Iterate over the various forms of propagation to simplify the theory.\n\n        Examples\n        ========\n\n        >>> from sympy.logic.algorithms.dpll2 import SATSolver\n        >>> l = SATSolver([set([2, -3]), set([1]), set([3, -3]), set([2, -2]),\n        ... set([3, -2])], set([1, 2, 3]), set([]))\n        >>> l.variable_set\n        [False, False, False, False]\n        >>> l.sentinels\n        {-3: set([0, 2]), -2: set([3, 4]), 2: set([0, 3]), 3: set([2, 4])}\n\n        >>> l._simplify()\n\n        >>> l.variable_set\n        [False, True, False, False]\n        >>> l.sentinels\n        {-3: set([0, 2]), -2: set([3, 4]), -1: set(), 2: set([0, 3]),\n        ...3: set([2, 4])}\n        ' #NEWLINE# changed = True #NEWLINE# while self : #NEWLINE# #INDENT# changed = False #NEWLINE# changed |= self . _unit_prop ( ) #NEWLINE# changed |= self . _pure_literal ( )