001    package aima.logic.fol.inference.proof;
002    
003    import java.util.List;
004    
005    /**
006     * @author Ciaran O'Reilly
007     * 
008     */
009    public interface ProofStep {
010            int getStepNumber();
011    
012            void setStepNumber(int step);
013            
014            List<ProofStep> getPredecessorSteps();
015    
016            String getProof();
017    
018            String getJustification();
019    }