Dear MAG members 

We would like to encourage as much feedback on the proposal for the effectiveTimes in the new OWLExpression file, to support the July 2019 logic profile enhancements. 

Please read through the following explanation of first the background, and then the intended direction for the July 2019 International Edition, and provide feedback on any major concerns or critical issues ASAP - but certainly before 23:00 UTC on 23rd June 2019: 

Logic Profile Enhancements 
The International Edition package will include both inactive Stated Relationships plus a complete OWL file from July 2019 effectiveTime onwards. In the July 2019 International Edition, this OWL file will contain only the history pertaining to OWL records that were included in earlier releases of the International Edition. No history of OWL records from the January 2019 optional "Demonstration" release package will be included in the July 2019 International Edition. 

We also plan to publish a separate optional package for the July 2019 International Edition, that contains an OWL Delta file with all changes to OWL axioms since the optional OWL Demonstration package published in January 2019. The optional Demonstration package from January 2019 contained a complete set of OWL axioms, for both concept definitions and attribute properties. 

No support for Stated Relationships will be provided from this point onwards, however we will continue to include the inactivated Stated Relationships in future International Edition packages, until it is decided that this is no longer required. 

Anyone who requires stated concept definitions, who isn’t yet ready to move forward with OWL will therefore remain on the January 2019 International Edition until they are ready to update to OWL with the July 2019 version onwards. 

The inferred relationship file will maintain the same format and structure as in previous releases. However, from July 2019 it will contain only a subset of the full semantics of the release. The inferred relationship file will represent the Necessary Normal Form for distribution of relationships, with only necessary conditions included. Most users will benefit from the improvements in the inferred relationships without requiring changes to their existing systems. Users should carefully analyze any potential impact to their systems and make provisions for these changes urgently (if not already done), in order to prevent any issues when these changes come into effect in July 2019. For more information, please contact SNOMED International at support@snomed.org with “OWL Axiom refset files implementation question” in the subject line. 

Note about Concept model object attribute and Concept model data attribute concepts 

The Concept model object attribute is the root of the Object Property hierarchy in the SNOMED OWL ontology but has also been made a subclass of Concept model attribute class. This is necessary in order to create the expected pragmatic link in the inferred form between the object attributes and the main concept hierarchy. The same is true for the Concept model data attribute which is the root of the Data Property hierarchy in the SNOMED OWL ontology. 

The effectiveTime and OWL expression refset 

In the July 2019 International Edition, it is the first release of the complete Snapshot of the OWLExpression refsets including all axioms converted from the stated relationships. The effectiveTime '20190731' has been assigned to all records for converted axioms, as it was in the two published complete OWL Demonstration releases. As a result, users and developers need to be aware of the potential impact to the effectiveTime and content of the OWLExpression refset. 

The decision was taken to re-version the concept definitions to 20190731 based on the established RF2 versioning principles, as (despite the stated relationships existing before this release) these OWLExpression reference set members themselves were not published prior to 20190731. 

As this decision has no impact on the inferred relationship file, this should not effect the majority of users. We will nonetheless provide additional support for those who need to identify the semantic changes in axioms, through the provision of an Optional release package. 

In the July 2019 International Edition, the Delta file for the OWLExpression refsets will include all axioms with effectiveTime '20190731'. This will include a mixture of axioms converted from stated relationships and new axioms. The Delta file will therefore show the differences between the OWLExpression Snapshot files in the January 2019 and July 2019 releases (as per normal practice). As mentioned above, a separate Delta file, containing the concept modelling changes since the January 2019 optional axiom release will be provided as an Optional package for July 2019. 

Please note that rows in the Snapshot file of the OWLExpression refset with an effectiveTime of '20190731' cannot be assumed to represent changes to the modelling of the associated concepts, because the majority of concept modelling will remain unchanged in this release. The Full file for the OWLExpression refsets will not include the history of changes to stated relationships. This will instead be found in the Full file for Stated Relationships, which will continue to be included in the International Edition (despite all stated relationships being inactivated in the July 2019 release). However, the Full OWLExpression file will include changes to axioms from both the January 2019 and the July 2018 release (when the partial OWL axiom refset and OWL ontology refsets were first released). Please note that this is different from the changes to stated relationships. If required, the complete history of changes to the stated relationships can be found by combining the Full stated relationship file, Full OWLExpression file in the Production International Edition, and the OWLExpression Delta file in the Optional release. 

A set of documentation has been developed to support the Logic Profile Enhancements: 

SNOMED DL Profile Enhancements - https://docs.google.com/document/d/1tqNEA6S4fEF4fgj15OPabYA2E0VTz8epxvRRwczKizQ/edit?usp=sharing 
SNOMED CT Logic Profile Specification - http://snomed.org/lps 
SNOMED CT OWL Guide (OWL Refsets specification) - http://snomed.org/owl 
Snomed OWL Toolkit - https://github.com/IHTSDO/snomed-owl-toolkit 
Classifying SNOMED CT using the Snomed OWL Toolkit - https://youtu.be/-91egY9mJqA 
Creating an OWL file containing SNOMED CT - https://youtu.be/sfFbMMioA_4

Thanks very much as always for all of your help