It is common knowledge in academia that article-based or cumulative PhD theses consisting of a collection of previously published papers are widely accepted and practiced.
The claim that a PhD thesis can consist entirely of previously published papers (commonly known as a cumulative or article-based dissertation) is a widely accepted institutional fact and everyday academic reality across many universities and disciplines (as referenced in passing by papers like [3]). No specific contested empirical dispute is at stake, making it a matter of common knowledge regarding academic structures.