Issue 16093: Incorrect statement about UML n-aries (sysml-rtf) Source: NIST (Dr. Conrad Bock, conrad.bock(at)nist.gov) Nature: Revision Severity: Significant Summary: Section 8.3.1.3 (UML Diagram Elements not Included in SysML Block Definition Diagrams) says "N-ary associations, shown in UML by a large open diamond with multiple branches, can be modeled by an intermediate block with no loss in expressive power." An intermediate block cannot capture multiplicities that would be on an the ends of an n-ary association. These multiplicities are for the links from end to end, rather than from intermediate object to end, as they would be with an intermediate object. However, intermediate blocks can specify the number of links each end might participate in for any of the other n-1 ends, which is not possible with n-ary associations. The expressiveness of n-aries and intermediate blocks is overlapping, rather than equivalent. Resolution: Defer Postponed to the next RTF Revised Text: Actions taken: March 22, 2011: received issue January 3, 2017: Deferred April 6, 2017: closed issue Discussion: End of Annotations:===== m: webmaster@omg.org Date: 22 Mar 2011 16:17:17 -0500 To: Subject: Issue/Bug Report ******************************************************************************* Name: Conrad Bock Employer: NIST mailFrom: conrad.bock@nist.gov Terms_Agreement: I agree Specification: Systems Modeling Language Section: Blocks FormalNumber: formal/2010-06-01 Version: 1.2 Doc_Year: 2010 Doc_Month: June Doc_Day: 01 Page: Title: Incorrect statement about UML n-aries Nature: Revision Severity: Significant CODE: 3TMw8 B1: Report Issue Description: Section 8.3.1.3 (UML Diagram Elements not Included in SysML Block Definition Diagrams) says "N-ary associations, shown in UML by a large open diamond with multiple branches, can be modeled by an intermediate block with no loss in expressive power." An intermediate block cannot capture multiplicities that would be on an the ends of an n-ary association. These multiplicities are for the links from end to end, rather than from intermediate object to end, as they would be with an intermediate object. However, intermediate blocks can specify the number of links each end might participate in for any of the other n-1 ends, which is not possible with n-ary associations. The expressiveness of n-aries and intermediate blocks is overlapping, rather than equivalent.