private final PdrEngine parent;
private final Director director;
private final List<Frame> F = new ArrayList<>();
private final PdrSmt Z;
private volatile boolean cancel = false;
<BUG>public PdrSubengine(String prop, Specification spec, boolean slicing, String scratchBase,

PdrEngine parent, Director director) {
super("pdr-" + prop);</BUG>
this.prop = prop;

private final PdrEngine parent;
private final Director director;
private final List<Frame> F = new ArrayList<>();
private final PdrSmt Z;
private volatile boolean cancel = false;
public PdrSubengine(String prop, Specification spec, String scratchBase, PdrEngine parent,
Director director) {
super("pdr-" + prop);
this.prop = prop;
