When I was writing biochemistry papers, it was a rule that you had to introduce the full spelling of a phrase along with the first use of its acronym in the full text. Is that not a thing anymore? This abstract reads like something out of a deep immunology subfield, and the first few paragraphs of the introduction didn’t help me out much either.
Well that is the norm if you use acronyms that are not well-known for the target audience. The paper you see is a submission to the SAT'26 conference, a conference dedicated to the problem SAT and related questions. For most people there, especially the ones interested in this paper, OBDD (Ordered Binary Decision Diagrams), FPT (Fixed Parameter Tractable), DNNF (Decomposable Negation Normal Form) and CNF (Conjunctive Normal Form) are pretty standard acronyms and you do not redefine them in every paper. Plus, conference format forces you to fit everything in a bounded number of pages, so you have to choose where to save space.
That said, Knowledge Compilation is one of the worst subfield of computer science regarding acronyms, so I understand your feeling...
Makes sense, and thank you for the expansions! Makes it easier to look them up