...

For inferred relationships in the Necessary Normal Form (NNF), SubclassOf, SubObjectProperty and SubDataProperty in the OWL refset should be represented as

Concept
ShowParts term t 116680003 |Is a|

 relationships. The explanation for the Necessary Normal Form and the rules for calculating the NNF can be found in the section 2.5. Generating Necessary Normal Form for Inferred Relationships from the OWL Refsets.
The following additional two 

Concept
ShowParts term t 116680003 |Is a|

 relationships should always be included in the inferred relationship file because they cannot be derived from the OWL axiom refset.

...

Attribute

SNOMED CT is based on concept and attribute is also concept. However, a property cannot be a subproperty of a class in OWL because class and property are disjoint.
Descendants of 

Concept
t 410662002|Concept model attribute (attribute)|

should be represented as either ObjectProperties or DataProperties in the OWL axiom refset. The rest SNOMED CT attributes including 

Concept
t 410662002|Concept model attribute (attribute)|

 should be represented as Classes in the OWL axiom refset.

...

Role group must be explicitly stated and represented by the attribute attribute 

Concept
t 609096000|Role group (attribute)|

in  in the OWL refset. Furthermore, role group should allow having only one attribute and value as "self grouped". These are key differences to the numeric number representation of role group in the RF2 relationship file.
For diagram of stated relationships in the OWL axiom refset, the attribute

Concept
t 609096000|Role group (attribute)|

should  should still be represented by a circle rather than an object property.

...