text: /*
   * All of the documentation and software included in the
   * Alchemy Software is copyrighted by Stanley Kok, Parag
   * Singla, Matthew Richardson, Pedro Domingos, Marc
   * Sumner, Hoifung Poon, and Daniel Lowd.
   * 
   * Copyright [2004-07] Stanley Kok, Parag Singla, Matthew
   * Richardson, Pedro Domingos, Marc Sumner, Hoifung
   * Poon, and Daniel Lowd. All rights reserved.
   * 
   * Contact: Pedro Domingos, University of Washington
   * (pedrod@cs.washington.edu).
   * 
   * Redistribution and use in source and binary forms, with
   * or without modification, are permitted provided that
   * the following conditions are met:
   * 
   * 1. Redistributions of source code must retain the above
   * copyright notice, this list of conditions and the
   * following disclaimer.
   * 
   * 2. Redistributions in binary form must reproduce the
   * above copyright notice, this list of conditions and the
   * following disclaimer in the documentation and/or other
   * materials provided with the distribution.
   * 
   * 3. All advertising materials mentioning features or use
   * of this software must display the following
   * acknowledgment: "This product includes software
   * developed by Stanley Kok, Parag Singla, Matthew
   * Richardson, Pedro Domingos, Marc Sumner, Hoifung
   * Poon, and Daniel Lowd in the Department of Computer Science and
   * Engineering at the University of Washington".
   * 
   * 4. Your publications acknowledge the use or
   * contribution made by the Software to your research
   * using the following citation(s): 
   * Stanley Kok, Parag Singla, Matthew Richardson and
   * Pedro Domingos (2005). "The Alchemy System for
   * Statistical Relational AI", Technical Report,
   * Department of Computer Science and Engineering,
   * University of Washington, Seattle, WA.
   * http://www.cs.washington.edu/ai/alchemy.
   * 
   * 5. Neither the name of the University of Washington nor
   * the names of its contributors may be used to endorse or
   * promote products derived from this software without
   * specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY OF WASHINGTON
   * AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY
   * OF WASHINGTON OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
   * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
   * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   * 
   */
  #include "powerset.h"
  PowerSet* PowerSet::ps_ = NULL;
  