Status: IN
The GoF's requirement that each pattern must demonstrate at least two real-system examples from different domains completes the formalization heritage inherited from Alexander: where Alexander's architectural concept required observing recurring solutions in existing buildings, the GoF operationalizes this empiricism as a minimum cross-domain evidence threshold, ensuring that documented patterns have been independently discovered rather than theoretically constructed.
Two-domain evidence requirement operationalizes Alexander's empirical principle
Depends on (SL): pattern-formalization-heritage, gof-known-uses-two-domains-minimum