1 /* This file is part of the project "Hilbert II" - http://www.qedeq.org" target="alexandria_uri">http://www.qedeq.org 2 * 3 * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. 4 * 5 * "Hilbert II" is free software; you can redistribute 6 * it and/or modify it under the terms of the GNU General Public 7 * License as published by the Free Software Foundation; either 8 * version 2 of the License, or (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 package org.qedeq.kernel.se.base.module; 17 18 import org.qedeq.kernel.se.base.list.Element; 19 20 21 /** 22 * Usage of substitute free subject variable by term. 23 * <pre> 24 * A(x) 25 * --------------- 26 * A(t) 27 * </pre> 28 * 29 * @author Michael Meyling 30 */ 31 public interface SubstFree extends Reason { 32 33 /** 34 * Get this reason. 35 * 36 * @return This reason. 37 */ 38 public SubstFree getSubstFree(); 39 40 /** 41 * Get reference to already proven formula. 42 * 43 * @return Reference to previously proved formula. 44 */ 45 public String getReference(); 46 47 /** 48 * Get free subject variable that should be replaced. 49 * 50 * @return Subject variable. 51 */ 52 public Element getSubjectVariable(); 53 54 /** 55 * Get replacement term. 56 * 57 * @return Replacement term. 58 */ 59 public Element getSubstituteTerm(); 60 61 }