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 * Rule of universal generalization. 23 * <pre> 24 * A -> B(x) 25 * ------------------- 26 * A -> forall x B(x) 27 * </pre> 28 * 29 * @author Michael Meyling 30 */ 31 public interface Universal extends Reason { 32 33 /** 34 * Get this reason. 35 * 36 * @return This reason. 37 */ 38 public Universal getUniversal(); 39 /** 40 * Get reference to formula. Usually this a formula of type A -> B(x) 41 * 42 * @return Reference to previously proved formula. 43 */ 44 public String getReference(); 45 46 /** 47 * Get free subject variable we want to quantify over. 48 * 49 * @return Free subject variable. 50 */ 51 public Element getSubjectVariable(); 52 53 }