diff --git a/framework/conformance.py b/framework/conformance.py
index 9a97ca4..ec8ae50 100644
--- a/framework/conformance.py
+++ b/framework/conformance.py
@@ -445,10 +445,12 @@ class Conformance:
                     candidate_element, = self.bottom.read_outgoing_elements(self.type_model, candidate_name)
                     candidate_source = self.type_model_names[self.bottom.read_edge_source(candidate_element)]
                     if candidate_source not in source_candidates:
-                        remove.add(candidate_name)
+                        if len(source_candidates.intersection(set(self.sub_types[candidate_source]))) == 0:
+                            remove.add(candidate_name)
                     candidate_target = self.type_model_names[self.bottom.read_edge_target(candidate_element)]
                     if candidate_target not in target_candidates:
-                        remove.add(candidate_name)
+                        if len(target_candidates.intersection(set(self.sub_types[candidate_target]))) == 0:
+                            remove.add(candidate_name)
                 self.candidates[m_name] = self.candidates[m_name].difference(remove)
 
     def build_morphisms(self):
diff --git a/framework/interactive_prompt.py b/framework/interactive_prompt.py
index ff38c8c..f0e9645 100644
--- a/framework/interactive_prompt.py
+++ b/framework/interactive_prompt.py
@@ -70,7 +70,7 @@ def main():
                         'filter': lambda x: False if x.lower() == 'false' else x
                     })
             args = prompt(args_questions)
-            args = {k: types[k](v) for k, v in args.items()}
+            args = {k: types[k](v) if len(v) > 0 else None for k, v in args.items()}
             try:
                 output = method(**args)
                 if output is not None: