Log — Mathematics Wiki

Append-only history. Entries start with ## [YYYY-MM-DD] <op> | <title>.

[2026-08-02] split | mathematics-wiki created from _inbox (3 sources)

Scaffolded from ../CLAUDE.template.md when mcmullen-probability-theory arrived over Telegram and completed a cluster the hub _inbox had already predicted. The two parked records did the analytical work before this spoke existed: fourier-analysis-for-beginners (2026-07-28) argued that Fourier analysis is infrastructure beneath four spokes and the subject of none, and set the trigger at three; vector-calculus-corral (2026-07-29) made the same argument for calculus, tallied two, and listed the shapes a third could take — with probability/statistics among them. The trigger source was the second item on that list.

Migrated sources. Three, under three different _inbox tags (mathematics, signal-processing, and the arriving course):

The Thibos PDF was git mv’d out of _inbox/ (it arrived over Telegram with no URL, so the held copy is the only one). Corral was re-fetched from mecmath.net, which returns HTTP 406 to curl’s default user-agent and serves the file to a browser one — noted on the source page so a future refetch failure isn’t read as a dead link. Both _inbox records deleted.

Pages. Three source summaries, four concepts (mathematics, probability-theory, vector-calculus, fourier-analysis), and six entities: curtis-mcmullen, michael-corral, larry-thibos, harvard-university, indiana-university, schoolcraft-college. entity-index matched none of them (the university-of-cambridge hits on Harvard and Indiana are the fuzzy matcher catching the word “University”). Two entity nodes per ingested source, well inside budget.

The naming question is open and recorded. The parked record flagged the fork — mathematics (the subject) versus quantitative methods (the use) — before the split. Called mathematics on the two-out-of-three: Corral and McMullen are unambiguously teaching the subject, and Thibos would sit in either. synthesis carries it as open question 1 so the next few sources settle it rather than the name deciding for them.

A deliberate non-move. ../machine-learning-wiki received information-theory-inference-learning-algorithms (MacKay) hours before this spoke existed, and roughly half of it is compression and coding theory that no spoke claimed at the time. The routing stands — it was correct on dominant substance and re-filing it now would be churn — but information and coding theory as a subject belongs here, and the CLAUDE.md scope boundary says the next such source lands here rather than dragging the first one over.

Founding weaknesses, recorded rather than discovered later. Every page rests on exactly one source; nothing is corroborated. There is no linear algebra and no analysis, which are the two largest holes under all three founding subjects. And the corpus’s provenance ranking runs opposite to its usefulness ranking — the T1 Harvard notes are the least self-sufficient of the three, the community-college text the most complete. synthesis makes both the founding tension.

avoid-ai-writing run over the founding prose. Site rebuilt + verified at the clean rung, as the hub requires for a split.

[2026-08-02] ingest | Elementary Calculus: An Infinitesimal Approach (Keisler, 1976/1986)

Arrived over Telegram the same afternoon the spoke was created, routed here by the hub. T1 — commercially published twice (Prindle, Weber & Schmidt 1976 and 1986; Dover third edition 2012), free online under CC BY-NC-SA since 2002, by a research mathematician. Held at raw/keisler-elementary-calculus.pdf (28.8 MB).

Reading it took work worth recording. The file is a 992-page scan with no text layer — pypdf returns empty strings for every page except the copyright notice. The first download truncated at 24.6 MB against a stated 28.8 MB and produced a corrupt PDF; a resumed fetch (curl -C -) fixed it. pdftoppm is unavailable on this device and there is no root to install poppler, so the front matter was read by extracting the embedded CCITT-G4 page images with pypdf, converting them to PNG with Pillow, and reading those visually. The author’s own calc.html supplied the edition and licence history. Method noted so the next scanned book doesn’t get parked as unreadable.

Pages. Source summary keisler-elementary-calculus plus one concept, infinitesimal-calculus. Updated vector-calculus (it now has two accounts), mathematics (four texts, and the analysis hole is partly filled), index and synthesis. Entities h-jerome-keisler and university-of-wisconsin-madison created; entity-index matched neither. Abraham Robinson and Sister Kathleen Sullivan are subjects of the book rather than agents around it, so they stay prose mentions per ../ENTITIES.md.

This is the ingest that gave the spoke something to argue about. Keisler’s chapters 10–13 cover corral-vector-calculus‘s entire book — gradients, line integrals, Green’s, Stokes, Gauss — so the corpus has its first corroboration. It also has its first disagreement, and the two are the same event: Corral assumes the limit-based Calculus I/II sequence as prerequisite, Keisler rebuilds it on hyperreals and defers limits to chapter 5. Recorded in synthesis as a foundational fork, stated carefully — the theorems agree, the pedagogy does not, and this is not a contradiction about mathematics.

Two more things the source changed. It breaks the spoke’s founding rigour-spectrum thesis: the other three sit at different points on one axis, and Keisler moves off the axis entirely by changing the foundation and claiming accessibility and rigour together. And it is the only source here with evidence for its pedagogy — a 1972–74 controlled experiment across five schools, in a Wisconsin PhD thesis and the American Mathematical Monthly — cited second-hand by the author in his own preface, which is weighed rather than taken at face value.

Open question 1 moved. The mathematics-versus-quantitative-methods naming call is now three of four; an argument about a subject’s foundations is not a quantitative method. Left open for one more source rather than closed.

Content-only, no page moves — verify deferred per the hub’s standing policy. avoid-ai-writing run over the new prose.

[2026-08-04] ingest | Hefferon, Linear Algebra (4th ed. 2020) — via research pass

Closes the spoke’s largest hole (synthesis open question 4 / growth edge 1): linear algebra sat under every text in the corpus and was the subject of none. Hunted against the hub’s ## Most wanted entry “mathematics-wiki · linear algebra + analysis”. T1.

Six pages, three of them new subject nodes: hefferon-linear-algebra (source, T1), jim-hefferon (Person), university-of-vermont (CollegeOrUniversity), and the linear-algebra concept page the index’s DefinedTerm group wanted.

The tier is argued on the page rather than asserted, because this corpus has already had one fight about grading. Free licence, free price and a LaTeX-on-Linux production stack are exactly what corral-vector-calculus has and they are not what earns the T1 — the MAA Solow Award (2020) does, being peer judgement in the sense the ladder means. That separation is the useful result: it makes licence and provenance independent axes, where the founding four had them confounded.

Hefferon also lands a third position on the rigour axis this spoke tracks. He proves everything and asks only one semester of calculus, paying for it in length rather than in omitted proofs — which is an argument that the rigour-versus-reach trade-off the corpus recorded is partly an artefact of page count. Noted in linear-algebra and folded into the provenance-versus-usefulness tension, which is weakened rather than withdrawn: this is the first source here where tier and reader value point the same way.

[2026-08-04] ingest | Trench, Introduction to Real Analysis (free ed. 2013) — via research pass

The second half of the same edge, and the spoke’s second T1. Four pages: trench-real-analysis (source), william-trench (Person), trinity-university (CollegeOrUniversity), real-analysis (concept).

T1 on different grounds from Hefferon’s — the book was a Pearson Education title before Trench reissued it free under CC BY-NC-SA once the rights reverted, so it carries a commercial publisher’s review that the corpus’s self-published texts do not. Two T1s earned two ways in one day is why the grading reasoning now sits on each page.

The interesting result is negative, and it goes to the foundational fork. Analysis is the course where the ε-δ choice stops being implicit — chapter 1 builds the reals from completeness and everything follows — so it is where an argument for the standard foundation would live if anyone were making one. Trench does not mention infinitesimals. That is a second text assuming the standard side and still nothing arguing it, which is a data point for Keisler’s inertia thesis and none for the merit reading. Promoted to growth edge 3: the spoke now wants a text that considered non-standard analysis and declined it in print. Closing two edges made the third one worse, which is worth recording as such.

Chapters 5–7 also give the corpus multivariable calculus a third time (corral-vector-calculus, Keisler ch. 10–13, Trench ch. 5–7), all three agreeing on results.

[2026-08-04] ingest | Larsen & Marx, An Introduction to Mathematical Statistics and Its Applications (5th ed.)

Routed here by the hub (runner-up: none). T1 — Prentice Hall / Pearson, fifth edition across 31 years (1981, 1986, 2001, 2006, 2012), two university professors, LC record QA276.L314 2012. Same grounds as trench-real-analysis and stronger, since this is a current commercial edition rather than a reverted one.

Closes growth edge 4 — statistics and inference, open since the split. Six pages: larsen-marx-mathematical-statistics (source), mathematical-statistics (concept), richard-larsen and morris-marx (Person), vanderbilt-university and university-of-west-florida (CollegeOrUniversity). The subject list in CLAUDE.md and the wikis.md registry were both refreshed — they still advertised linear algebra, analysis and statistics as wanted, three days after two of them closed and hours before the third did.

Fetch note. The PDF is 11 MB and exceeded the fetcher’s limit, so it was downloaded and its text extracted locally rather than skipped or stubbed. Title, authors, both institutions, publisher, edition history, copyright and the full fourteen-chapter table of contents are read from the file itself, not inferred from the filename.

What makes it worth more than a syllabus. Every chapter closes with “Taking a Second Look at Statistics” — short essays on how the machinery just taught misleads: statistical versus “practical” significance, how not to interpret a sample correlation coefficient, why samples are never “valid,” outliers, Type II error. A text that spends a section per chapter undercutting itself is doing something no other source in this corpus does, and it is the natural counterpart to ../quant-trading-wiki’s backtest-overfitting material.

It breaks the corpus’s licence pattern, and that is recorded rather than smoothed. The other five texts are free by licence — GFDL, CC, or an author’s own university web space. This one is © 2012 Pearson, all rights reserved, read from a PDF on an Emory course page. It is the first text here that is accessible without being freely licensed, two properties the corpus had been treating as one because they had always arrived together. New growth edge 5: a freely-licensed statistics text.

Two open questions moved. The origin-predicts-quality thread gains its sharpest case — a regional public university and a private research university co-authored one text, indistinguishably — and the institution and the publisher finally come apart, having been the same fact for five texts. And the research-methods fork, flagged in CLAUDE.md before the split and dormant since, is now live: this book contains ANOVA and randomized block designs, which is experimental design. Read as strengthening the mathematics side (it derives its distributions and proves its theorems, where a research-methods text would give protocols), but the next statistics source decides it.

[2026-08-06] ingest | Understanding Statistics and Experimental Design (hub-routed, Telegram, T1, open access)

Herzog, Francis & Clarke, Springer Learning Materials in Biosciences, 2019, 142pp, CC BY-NC 4.0. Arrived as a Springer PDF link; the direct PDF and the book page both 303’d to an auth endpoint, so the metadata came via firecrawl and the full text from a direct curl of the open-access PDF (146 pages).

Created herzog-understanding-statistics (Book, url-only, T1) plus four entity nodes: michael-herzog, gregory-francis, epfl, purdue-university — 4 of the 8 budget; Aaron Clarke (Bilkent) kept as a plain mention. Entity-index caution recorded on two pages: the index returned MATCH for “Michael Herzog”→michael-corral and “Purdue University”→university-of-cambridge, both false positives on name shape. New nodes created; the Herzog/Corral collision is noted on the page itself so a later pass does not “fix” it by merging.

Closed growth edge #5 (a freely-licensed statistics text) with the qualification kept: CC BY-NC is free to read and share but carries a non-commercial restriction that hefferon-linear-algebra and trench-real-analysis do not, so the edge is closed by the weaker kind of open.

mathematical-statistics refreshed in place rather than duplicated — it now names two accounts at two altitudes (Larsen & Marx derives the machinery; this teaches its use) and gained a section on the Test for Excess Success: sum the power across a set of studies and compare with the number of significant results. Precognition, ten experiments: 6.27 expected vs 9 reported, p = 0.058. Bystander effect, nineteen studies: 10.77 expected vs 10 reported, p = 0.76 — the test separates rather than condemns. Consequence recorded for the concept page: at moderate power, power becomes a parameter for reading someone else’s result, not only for planning your own, and the authors state that replication cannot be the final arbiter unless power is very high.

Open question 5 (the research-methods fork) answered against the easy reading. That question said the next statistics source would decide the fork. This one has no derivations and spends a third of its length on research practice — by the question’s own test it votes for the fork. Routed here anyway under the spoke’s first-principles boundary rule, with the reasoning written into the synthesis rather than hidden, and a stated trigger: a second source of this shape should split the spoke, not generate another routing note.

Cross-spoke context noted on the source page, not fragmented: chapters 10–12 are the psychology replication crisis (Open Science Collaboration 36% of 97 studies; Amgen 47 of 53 cancer papers), which is psychology-wiki’s standing caveat and the runner-up destination; the TES generalizes to any literature reporting many significant results, touching agentic-tooling-wiki and quant-trading-wiki.

[2026-08-06] ingest | Measurement Across the Sciences (Mari, Wilson & Maul — hub-routed, Telegram, URL-only, T1)

Springer, 2nd ed. 2023, 307pp, open access CC BY 4.0 — the corpus’s first unrestricted open licence (Herzog is CC BY-NC; Keisler and Trench are NC-SA). Created source summary mari-measurement-across-sciences (Book, url-only, T1 — peer-reviewed monograph in the Springer Series in Measurement Science and Technology) and a new subject page measurement-theory, plus six entity nodes: luca-mari / mark-wilson / andrew-maul and liuc / uc-berkeley / uc-santa-barbara (first non-US institution and first engineering school in the corpus; two of the three authors sit in schools of education, not mathematics departments).

Substance. Four necessary conditions for a process to be a measurement (empirical · designed on purpose · input is a property of an object · output is values of that property), then several hundred pages hunting sufficient ones. Model-dependent realism as the position (ch. 4), taking parts of naive realism, operationalism and representationalism while rejecting their strong forms; two consequences worth recording because they contradict the usual account — measurement is not quantification, and a result is not a preexisting true value being transmitted. Ontology of properties and scale types (chs. 5–6), a general process model with the new Hexagon Framework for measurand identification (ch. 7), and a semiotic close (ch. 8). Temperature and reading-comprehension ability run as paired examples throughout, chosen to be as far apart as possible.

The most useful piece for this corpus is ch. 3’s split: the physical sciences answer imperfect measurement with uncertainty (a set of compatible values, made portable by traceability to units), the human sciences with validity (does the procedure measure the intended construct). One question, two literatures, little contact. Folded into mathematical-statistics as a new “What happens before the data” section — inference begins once numbers exist, and nothing in Larsen & Marx or herzog-understanding-statistics asks whether the measurand was well defined.

Routing is arguable and recorded as such. This is the first source here that is not mathematics: it is measurement science and philosophy of measurement, with no theorem the spoke would otherwise hold. Carried on three grounds — no hub spoke owns measurement as a subject, at least three borrow it, and the spoke’s boundary rule files a first-principles theory text here. ../psychology-wiki was runner-up (psychometrics/validity), ../philosophy-wiki declined (it owns philosophers and their systems, not philosophy of science). Opened open question 7 in synthesis.md, which reads this as evidence for the quantitative methods answer to open question 1 rather than as the research-methods fork of question 5 — the book sits under both. Condition to watch: a second measurement-science source makes a cluster the hub could spin out instead of a stretch this spoke absorbs.

Also refreshed mathematics, whose corpus table had been stale since 2026-08-04 (listed four texts and called linear algebra the largest hole after Hefferon closed it) — now eight texts across seven subjects, with the missing-subjects paragraph rewritten and a short “odd one out” note for measurement theory.

[2026-08-06] ingest | Elementary Probability, 2nd ed. (Stirzaker — hub-routed, Telegram, URL-only, T1)

Cambridge University Press, 2003, 538pp, © CUP — read from a PDF on ctanujit.org, a third-party teaching site whose right to host it is not established. Created source summary stirzaker-elementary-probability (Book, url-only, T1) plus david-stirzaker (Person) and university-of-oxford (CollegeOrUniversity). The shared URL carried an fbclid Facebook tracker, stripped before recording — the same shape as the mcmullen-probability-theory link, so both probability sources here arrived through a social share.

Second account of probability-theory, and a different kind of second account. The vector-calculus pair disagrees about foundations; this pair agrees about the mathematics and differs in how much the reader must supply — 98 terse pages with Feller assumed, against a self-contained course with worked examples, clustered exercises, end-of-chapter problems and solutions. Coverage overlaps heavily for six chapters, then Stirzaker continues into the material McMullen never reaches: martingales and optional stopping, Markov chains, the Poisson process, and the Wiener process and diffusions. Added a “Where the subject continues: stochastic processes” section to probability-theory for that layer, and widened the ../quant-trading-wiki cross-note — the second edition added Brownian motion because it underpins Black–Scholes, which is the first time this spoke’s corpus reaches option-pricing mathematics from the theory side.

Pedagogy thread. Stirzaker defends the formal definition of probability “not because of high principles, but merely because the alternative intuitive approach seems to lead more students into errors” — Keisler’s kind of argument, about student outcomes, reaching the opposite conclusion in a different subject and with no data behind it. Folded into the rigour-spectrum section of synthesis.md: both authors who argue their foundation choice argue it on pedagogy, not principle. Also noted that his chapter 0 opens on determinism and “what is probability really”, then explicitly refuses to let the answer matter — McMullen’s notes open the same way. Both probability texts here start with philosophy and then wall it off.

Licensing. Second in-copyright text in the corpus after larsen-marx-mathematical-statistics, and both exceptions to the free-by-licence pattern are commercially published probability/statistics books. Recorded on the page rather than smoothed over.

Spine updates: probability-theory (two new sections, header rewritten), mathematics (corpus table, nine texts), index.md (stale header note fixed — it still said only vector-calculus was doubled), synthesis.md (single-sourcing paragraph, rigour spectrum, open question 1).

[2026-08-08] ingest | Algebra 1: Groups, Rings, Fields and Arithmetic (Ramji Lal, Springer 2017)

Routed from the hub (Telegram). T1 — Springer academic textbook, Infosys Science Foundation Series (Mathematical Sciences), DOI 10.1007/978-981-10-4253-9, 11 chapters / ~433pp, volume one of three.

New pages: lal-algebra-1 (source summary), abstract-algebra (subject), plus entities ramji-lal, harish-chandra-research-institute, springer and infosys-science-foundation-series.

Closes growth edge 7 — abstract algebra and number theory, the last untouched subject on the list and the structural layer under linear-algebra. Partially: the edge asked for an open textbook and this one is commercial ($49.99 eBook / $89.99 hardcover), so the licence half is refiled as its own edge (8), together with the parts of algebra this volume does not reach — Galois theory, modules, representation theory, all in Lal’s later volumes.

Provenance, stated on the page. The link that arrived was a scanned PDF on a file-sharing service. I documented the book from the publisher’s own page — description, chapter list, pagination, series, price — and did not read the body. Every claim on the page is about the book’s scope and position, none about the mathematics inside.

Folded into synthesis as “Paid first, free second.” Statistics arrived paid (larsen-marx-mathematical-statistics) with an open text following two days later (herzog-understanding-statistics); algebra has now arrived paid. The point is about this wiki’s own collection policy — a corpus that accepted only open licences would have neither subject today — and springer makes it from the publisher side, issuing both the paywalled algebra text and the open-access statistics one.

Structural note worth keeping: Lal puts two chapters of logic and set theory before any algebra. The spoke’s foundations argument so far has been about which foundation to stand on (Keisler’s infinitesimals, Stirzaker’s formal definitions); this is a text that simply teaches the foundation first. A table of contents cannot say whether that works.

Entities: 4 created, 0 linked. entity-index matched “Springer” to behringer (music-tech) — a substring false positive, not a duplicate; the memory note about that failure mode holds.

[2026-08-08] ingest | Abstract Algebra: Theory and Applications (Thomas Judson) — research pull

Curator asked for depth on algebra beyond what lal-algebra-1‘s publisher page could support. The honest way to get it was a text I can actually read, so I pulled judson-abstract-algebra (GNU FDL, maintained since 1997, 23 chapters) — T1, read from the 2012 PDF mirrored on a Colorado State course page since abstract.ups.edu was unreachable from this host.

Closes growth edge 8 the same day it opened. Edge 8 (an open-licensed algebra text) was created hours earlier when lal-algebra-1 closed the subject and left the licence half unmet. Judson also carries Galois theory to the fundamental theorem, which Lal defers to a later volume. What remains open in algebra: modules and representation theory, in neither book.

New pages: judson-abstract-algebra, group-theory, plus entities thomas-judson and stephen-f-austin-state-university. abstract-algebra rewritten to rest on read definitions — the group axioms, and the ring → commutative ring → integral domain → division ring → field hierarchy with the separating examples (ℤ a domain but not a field, ℤ₁₂’s zero divisors 3·4 ≡ 0, 2×2 matrices as a noncommutative ring, the quaternions as a noncommutative division ring).

lal-algebra-1 enriched with its eleven public chapter abstracts — Springer’s own metadata, not the chapters. They fix the scope precisely: Zermelo–Fraenkel with choice over Gödel–Bernays, number systems from Peano’s axioms, Lagrange and the isomorphism theorems, permutation and matrix groups as “the two main sources of groups”, Sylow, Schreier/Jordan–Hölder, Remak–Krull–Schmidt, quadratic reciprocity.

Synthesis records what the pair buys: the corpus’s first subject to arrive with two treatments that disagree about what a first course is for — foundations-first and classification-heavy (Lal) against applications-forward and Galois-complete (Judson), with Judson stating the reason in his preface (applications motivate students meeting rigorous proof for the first time). That is this corpus’s recurring unmeasured pedagogical argument, now about content selection rather than rigour.

Standing asymmetry, recorded on every page that compares them: Judson’s body was read, Lal’s was not. Comparisons are of stated scope, not of exposition.

Entities: 2 created.

[2026-08-10] ingest | A Course in Game Theory (Osborne & Rubinstein, 1994)

Routed from the hub — a 372-page Internet Archive scan of the MIT Press graduate text, sent by the curator over Telegram. T1, held in raw/ and read directly (preface, Chapter 1, the Chapter 2 and 3 definitions, and the full table of contents; the OCR mangles symbols, so the source page quotes prose and paraphrases formulas).

A new subject, and a text that denies it belongs here. game-theory is the corpus’s twelfth text and its tenth body of theory. The routing is straightforward under the boundary rule — a text teaching a body of theory from first principles, examples from economics — but the rule had to override the authors themselves for the first time. Osborne and Rubinstein state that they treat game theory “not as a branch of mathematics but as a social science,” and that in principle the same book could be written “devoid of mathematics.” They then give precise definitions and full proofs for 373 pages. Recorded in synthesis rather than argued away.

New pages: osborne-rubinstein-course-in-game-theory, game-theory, plus entities martin-j-osborne, ariel-rubinstein, mit-press, mcmaster-university, tel-aviv-university. mathematics table corrected — it had also fallen behind on abstract-algebra, which had a page but no row.

Two growth edges opened (12 and 13). The book assumes von Neumann–Morgenstern utility and Savage probability and explicitly declines to defend them, so game-theory rests on decision-theoretic foundations no page here states. And the authors name their own gaps: experimental game theory, and learning and evolution, two chapters they say they would add if writing now. Mechanism design is present only as Chapter 10’s pure implementation theory.

Cross-spoke tension recorded, not resolved. The rationality assumptions are, in the authors’ words, “under perpetual attack by experimental psychologists” — that attack is the heuristics-and-biases material in ../psychology-wiki, and nothing in this corpus can adjudicate between them.

Entities: 5 created.

[2026-08-10] ingest | Carroll, Geometric Function Theory — the corpus’s first second course

Routed from the hub; a PDF, not a URL — sent to Telegram as a document, downloaded, extracted with pypdf locally per the standing rule, and the file placed in raw/carroll-geometric-function-theory.pdf. Springer 2024, SUMS, 358pp, ISBN 978-3-031-73726-8. T1, read in the original for structure, preface and scope rather than worked through — the page says so.

New pages: carroll-geometric-function-theory (source), complex-analysis (field), tom-carroll (author), university-college-cork (institution), springer-undergraduate-mathematics-series (series). springer updated in place — third title, and it lands in the middle of that node’s access axis rather than at either end.

The finding, and it is about curricula rather than mathematics. Every text here so far teaches a first course, and the whole rigour-spectrum argument in synthesis is authors disagreeing about how to teach a syllabus none of them chose. Carroll’s preface names why that was possible: there is “general agreement” on the first-course list, and “this consensus evaporates when it comes to a second course.” Settledness is a property of a subject’s first year, and it ends.

What he does about it: §1.4, “What Is Not in This Book” — an explicit non-goals section naming the omissions (curvature, conformal invariants past the hyperbolic metric, Riemann surfaces beyond the sphere, Denjoy–Wolff) and where each is treated properly. No other text in this corpus has one. The nearest comparison, coding-interview-university in ../engineering-education-wiki, announces exclusions too — but an exam dictates those and nothing dictates these.

A pedagogy result the corpus had been misattributing. 54 pages of complete worked solutions, and no computational tool assumed (no Sage, no Matlab). Both come from the SUMS series specification, so this is the first case here of a publisher setting pedagogy where the spoke had been reading such choices as authorial.

Two new growth edges (15, 16), and an admission with them: complex analysis was never on the edge list at all. The shelf ran calculus → analysis → algebra and skipped the complex plane through eight revisions of that list — which says something about the method, since edge-listing catches subjects the existing sources gesture at and misses the ones they never mention.

[2026-08-12] ingest | Illowsky & Dean, Introductory Statistics 2e (OpenStax)

Arrived via Telegram as a PDF link (assets.openstax.org); the URL carried Google-Analytics linker params (_gl=…), stripped before recording. Routed here by the hub: probability, statistical inference and the pedagogy around them are this spoke’s domain. PDF held in raw/ as illowsky-introductory-statistics.pdf (23 MB, 847pp) and read locally with pypdf — front matter, full contents, and the preface in full.

Source: illowsky-introductory-statistics — OpenStax / Rice University, ©2026, CC BY-NC-SA 4.0, built 2026-04-20. Senior contributing authors Barbara Illowsky and Susan Dean of De Anza College; grown out of their earlier Collaborative Statistics. T1, whole text read.

New pages: 5. The source plus openstax, barbara-illowsky, susan-dean and de-anza-college. Updated: mathematical-statistics, synthesis, index.md.

What it gives the corpus. A rigour floor stated as policy rather than reached by omission: “focuses on statistics application over theory,” for “students majoring in fields other than math or engineering,” assuming intermediate algebra. It reaches confidence intervals, two-sample testing, chi-square, regression and one-way ANOVA with no calculus and no proofs. Against larsen-marx-mathematical-statistics on the same tests, that is the spoke’s cleanest pairing yet on what a derivation is actually for — recorded on mathematical-statistics as two subjects sharing a vocabulary rather than as better and worse books.

The assumed-tool observation paid off. CLAUDE.md asks for the computational tool alongside the tier. Three data points now: carroll-geometric-function-theory assumes none and proves everything, judson-abstract-algebra assumes Sage and proves everything, this assumes a TI-83/84 and proves nothing. The calculator supplies the numbers a derivation would have justified.

A new publisher shape. Every prior open text here was author-released; openstax is institutional publishing with the licence applied at the end. The tell is in the preface: revisions keep problem numbering stable so online homework providers can move editions with minimal impact. No other source here reports downstream-integration pressure on a textbook. Also recorded: the licence is CC BY-NC-SA, so “free textbook” does not mean unrestricted reuse.

2e changes, stated: “currency, relevance, accuracy, and belonging” — several hundred edits on gender, race, ethnicity, age, academic status and societal issues; data and references refreshed; the mathematics unchanged.

Entities: 4 created, all new to the hub (no OpenStax, Illowsky, Dean or De Anza page existed anywhere before today).