         }
     }
     
-    private func merge(polynomialA:DPolynomial, polynomialB:DPolynomial)
+    private func merge(
+        polynomialA:DPolynomial,
+        polynomialB:DPolynomial,
+        inverse:Bool)
     {
         let aSign:Double
         let bSign:Double

        {
            merge(
                polynomialA:polynomial,
                polynomialB:result)
            
            DManager.sharedInstance?.createManagedObject(
                entityName:DPolynomial.entityName)

        {
            merge(
                polynomialA:polynomial,
                polynomialB:compare,
                inverse:false)
            
            equation.removeFromPolynomials(compare)
            DManager.sharedInstance?.delete(object:compare)
