What precisely is a synthetic paper?
The term synthetic can have different meanings. In this context the definition of the word "synthesis" is helpful:
- The combining of separate elements or substances to form a coherent whole.
- The complex whole so formed.
A synthetic paper is a paper that summarizes results and ideas from various origins to form a (hopefully) coherent statement or conclusion.
Synthetic papers are sort of critical reviews that describe important concepts in, often, multidisciplinary fields. These papers are often structured and written in a (slightly) different way than typical reviews (or normal papers).
For example, the synthetic papers in your post describe important concepts that link together mathematics, logic, and computation.