AI research vocabulary index (weekly)

Weekly index of the technical vocabulary driving AI research, mined from the titles and abstracts of every AI paper announced on arXiv in the trailing 7 complete days (cs.AI, cs.CL, cs.CV, cs.LG via the official keyless arXiv query API, 3 s between requests per the API Terms of Use). Deterministic pipeline: LaTeX stripped, hyphenated/spaced spellings merged, plural stemming, stopword + domain-filler screening, document-frequency filter (term must appear in >= 3 papers and <= 50% of the weekly corpus). Each term is scored by TF-IDF-style significance ln(N / df) * mean(1 + ln(tf)) over containing papers, min-max normalized 0-100, and ranked (significance desc, term_id asc). Each term carries a majority-vote AI subtopic (agents, reasoning, evals, llm, finetuning, rl, quantization, multimodal, vision, audio, nlp, robotics, ml-theory, data, education, other), up to 5 sample arXiv ids, and an example paper title. Columns: ISO week, day-granular fetch timestamp, deterministic term_id, display term, token count, paper count, paper share, significance score, emergence rank, AI subtopic, sample arXiv ids, example paper title, first-seen week, week-over-week velocity (attached automatically from the second snapshot on, when a prior snapshot exists in the hub; absent from the baseline snapshot). Primary key: (week, term_id). Cadence: weekly. Nullability: velocity_pct is absent from the first snapshot; every emitted column is otherwise never null. Caveats: subtopic is a keyword-rule majority vote, not a classifier; stemming is a small deterministic rule set, not a lemmatizer; significance measures vocabulary distinctiveness, not research quality. Only descriptive arXiv metadata is mined (CC0 1.0), so commercial_use = yes. Sample use: order by emergence_rank for the week's most distinctive technical vocabulary, or filter ai_subtopic = 'agents'.