removed obsolete store_thm(s), cf. functional versions in pure_thy.ML;
tuned;
/***************************************************************************
  Title:      GraphBrowser/DummyVertex.java
  ID:         $Id$
  Author:     Stefan Berghofer, TU Muenchen
  Copyright   1997  TU Muenchen
  This class represents a dummy vertex, which is used to simplify the
  layout algorithm.
***************************************************************************/
package GraphBrowser;
import java.awt.*;
class DummyVertex extends Vertex {
	public boolean isDummy() {return true;}
	public Object clone() {
		Vertex ve=new DummyVertex();
		ve.setX(getX());ve.setY(getY());
		return ve;
	}
	public int leftX() { return getX(); }
	public int rightX() { return getX(); }
	public void draw(Graphics g) {}
}