code: private void setStrongestMapping(INode source, INode target) {
          //if it's structure preserving
          if (isSameStructure(source, target)) {
              spsmMapping.setRelation(source, target, defautlMappings.getRelation(source, target));
  
              //deletes all the less precedent relations for the same source node
              for (INode node : defautlMappings.getTargetContext().getNodesList()) {
                  //if its not the target of the mapping elements and the relation is weaker
                  if (source != node && defautlMappings.getRelation(source, node) != IMappingElement.IDK
                          && isPrecedent(defautlMappings.getRelation(source, target), defautlMappings.getRelation(source, node))) {
                      defautlMappings.setRelation(source, node, IMappingElement.IDK);
                  }
              }
  
              //deletes all the less precedent relations for the same target node
              for (INode node : defautlMappings.getSourceContext().getNodesList()) {
                  if (target != node) {
                      defautlMappings.setRelation(node, target, IMappingElement.IDK);
                  }
              }
          } else {
              //the elements are not in the same structure, look for the correct relation
              computeStrongestMappingForSource(source);
          }
      }
docs: Sets the relation between source and target as the strongest in the temp, setting all the other relations
  for the same source as IDK if the relations are weaker.
  
  @param source source node
  @param target target node