The "Summary" section in the table states the following mandatory requirement:

7. One or more DiagnosticReport.result and/or one or more DiagnosticReport.presentedForm

Since one and/or the other is required, each attribute has lower cardinality 0 (which is appropriate for the "or" case). There is not an invariant (e.g., FHIRPath constraint) to enforce that at least one of the attributes must be present. Therefore, this is a mandatory requirement that isn't represented in a structured way (but could be).

I think the FHIRPath constraint would be fairly simple. Something like result.exists() or presentedForm.exists().