Running Thread.stop() against 1784905630Exec. 256, QDPReductionPair[Order=PMatroNat[Collapse=True, Dimension=2, Range=1, Engine=MINISAT], Active=True, MergeMutual=True, Allstrict=False]
Stack trace:
    java.base/java.util.Collections.singletonIterator(Collections.java:5136)
    java.base/java.util.Collections$SingletonSet.iterator(Collections.java:5225)
    immutables.DefaultImmutableSet.iterator(DefaultImmutableSet.java:168)
    java.base/java.util.AbstractCollection.addAll(AbstractCollection.java:337)
    aprove.verification.dpframework.Orders.Utility.GPOLO.OrderPoly.calculateInnerVariables(OrderPoly.java:90)
    aprove.verification.dpframework.Orders.Utility.GPOLO.OrderPoly.<init>(OrderPoly.java:59)
    aprove.verification.dpframework.Orders.Utility.GPOLO.OrderPolyFactory.wrap(OrderPolyFactory.java:63)
    aprove.verification.dpframework.Orders.Utility.GPOLO.OrderPolyFactory.substituteVariables(OrderPolyFactory.java:177)
    aprove.verification.oldframework.Algebra.PolyMatrices.PolyMatrixFactory.substituteVariables(PolyMatrixFactory.java:403)
    aprove.verification.dpframework.Orders.Utility.PMATRO.AbstractPolyMatrixInterpretation.interpretTerm(AbstractPolyMatrixInterpretation.java:286)
    aprove.verification.dpframework.Orders.Utility.PMATRO.AbstractPolyMatrixInterpretation.interpretTerm(AbstractPolyMatrixInterpretation.java:276)
    aprove.verification.dpframework.Orders.Utility.PMATRO.AbstractPolyMatrixInterpretation.interpretTerm(AbstractPolyMatrixInterpretation.java:276)
    aprove.verification.dpframework.Orders.Utility.PMATRO.NatPolyMatrixInterpretation.fromTermConstraints(NatPolyMatrixInterpretation.java:205)
    aprove.verification.dpframework.DPProblem.Solvers.PMatroNatSolver.doSolve(PMatroNatSolver.java:274)
    aprove.verification.dpframework.DPProblem.Solvers.PMatroNatSolver.solveQActive(PMatroNatSolver.java:200)
    aprove.verification.dpframework.DPProblem.Processors.QDPReductionPairProcessor.processQDPProblem(QDPReductionPairProcessor.java:199)
    aprove.verification.dpframework.DPProblem.Processors.QDPProblemProcessor.process(QDPProblemProcessor.java:47)
    aprove.strategies.ExecutableStrategies.Executor.execute(Executor.java:326)
    aprove.strategies.ExecutableStrategies.Executor$Runner.wrappedRun(Executor.java:377)
    aprove.strategies.Abortions.PooledJob.run(PooledJob.java:99)
    aprove.strategies.Util.PrioritizableThreadPool$Worker.run(PrioritizableThreadPool.java:274)
    java.base/java.lang.Thread.run(Thread.java:1474)
