Levi Neuwirth

• Ball-Occupation Certificates under Coarse Graph Projections 27 July 2026

  We isolate an abstract strategy-transfer principle for Cops and Robber: a coarse graph projection with bounded fibers and bounded distance distortion lets cops occupy a lifted macro-ball before the robber escapes, giving cop number O(sqrt N) up to polylogarithmic factors. Applied to the Hosseini-Mohar-Gonzalez Hermosillo de la Maza degree-reduction construction, this shows the known hard family for Meyniel’s conjecture already meets the square-root exponent, sharper than the usual notation suggests. A counting argument then proves a sharp limit on the strategy class itself: Cartesian tori of cycles have bounded doubling and constant cop number but linear occupation cost at every radius, so weak expansion alone cannot certify a universal robustness theorem.

  researchresearch/mathematicsresearch/graph-theory
• The Annealed Critical Window for Growing-Radius Domination in Random Regular Graphs 22 July 2026

  A complete determination of the bounded annealed critical window for growing-radius domination in random regular graphs, resolving the open problem left by an earlier near-critical bound. Writing L_h = log B_h for the radius-h tree-ball volume, the annealed exponent obeys a universal scaling law (B_h/L_h^2) Psi_{d,h}((L_h - 2 log L_h + s)/B_h) -> 1 - e^{-s}, and its lower zero is pinned to within B_h^{-1/7+o(1)} of the scalar coupon-collector root H(C/B_h) = (1-C/B_h)^{B_h}, giving a complete fixed-order inverse-logarithmic expansion. The proof adds a quantitative reverse-transfer error analysis and an explicit capped-free profile whose only entropy loss is the cost of one terminal nonemptiness event, sharpening the earlier annealed lower bound into a two-sided window theorem. The result again strengthens to internally two-path domination, a graph-general parameter motivated by exhaustive static tube coverage in pursuit-evasion games. Quenched matching and the direct two-branch leading constant remain open.

  researchresearch/mathematicsresearch/graph-theory
• From Path Tubes to a Near-Critical Domination Bound 22 July 2026

  A first-person, code-heavy companion to the preprint Near-Critical First-Moment Lower Bounds for Growing-Radius Domination in Random Regular Graphs. Rather than reproducing its theorem-and-proof form, this page traces where the problem came from — a cops-and-robbers hypergraph question that collapsed into a domination bound — why the answer carries an unnecessary coupon-collector logarithm, and how a chain of computational detours (a failed concavity conjecture, a catastrophic cancellation, an independent audit that caught a stale constant) repeatedly redirected the proof before it reached its final shape.

  researchresearch/mathematicsresearch/graph-theorytech/python
• Branch-Tube Persistence and Static Coverage in Tree-Ball Geometry 21 July 2026

  We analyze exhaustive static coverage by path tubes indexed by length-$t$ nonbacktracking robber paths from $v_0$ in a finite-horizon local chase on a $d$-regular graph. An endpoint-sensitive geodesic lemma shows that, among possibly infinite $d$-regular graphs, radius $R+t$ is sharp for arbitrary pairs in $B_R(v_0)\times B_t(v_0)$, while synchronized witnesses along a prescribed path require only a radius-$R$ tree-ball. If every tube is occupied, each surviving round along every path in this class ends in capture, blockage, or branch-load support on at least two branches. The tubes partition the outer ball, so deterministic coverage has minimum cost $N_t=d(d-1)^{t-1}$; conditional on a specified root, i.i.d. uniform coverage has threshold $\Theta(N_t\log N_t)$ for fixed $d$. An augmented prefix-depth profile that retains the complete shallow configuration still need not determine later support. The result is local and root-dependent: it treats neither arbitrary robber walks nor a robber-independent cop strategy, and it gives no cop-number bound.

  researchresearch/mathematicsresearch/graph-theory
• Asymmetric Forgetting 26 May 2026

  Curricula in mathematics and the sciences optimize for procedural fluency — the half of what they teach that decays once the student stops being a student. What survives twenty years on is conceptual residue, generated only as an accidental byproduct of the curriculum’s intended work. The asymmetry compounds across generations of teachers and produces a population unable to do the work that civic life requires of it.

  educationnonfictionnonfiction/philosophypolitical
• The Specification Dilemma 1 May 2026

  As we approach AGI, the increase in the ability of Artificial Intelligence models to infer a robust specification from a sparse prompt will lead to a devastating trend of homogeneity. We argue that this is the primary concern regarding the interaction of AI and human intelligence, rather than blanket claims that “AI reduces human cognitive ability.”

  aillmmiscellanynonfictionphilosophytechtft
• LeVCS: A Distributed Version Control System 1 May 2026

  LeVCS is a distributed version control system in the lineage of git, fossil, pijul, and sapling — content-addressed objects, signed history, three-way merge — with five things deliberately rebuilt: identity in the protocol, federation as a first-class concept, a cascading merge engine that dispatches per-file to format-aware and tree-sitter handlers, BLAKE3 hashing throughout, and releases as signed artifacts rather than mutable name pointers. v0.1.0 ships the protocol substrate; the workflow surface — review, issues, web UI — is the next layer up.

  systemsprojectsreleases
• Weenix 21 April 2026

  Full Unix-like kernel in ~7,000 lines of C, written for Brown CS 169 (Operating Systems with Lab): virtual memory, VFS, system calls, threading, device drivers and interrupt handlers, and file systems. Custom linker support for running userspace x86-64 ELF binaries.

  techtech/C
• NeuroPose 21 April 2026

  3D pose-estimation and kinematic-analysis system for neurological-recovery research, developed in Liqi Shu’s laboratory at the Brown University Department of Neurology. Python/TensorFlow inference, MATLAB-based statistical post-processing, Rust backend with HTML/JS frontends. Four externally-funded sub-projects since 2023; clinical-implications manuscript in preparation.

  researchresearch/machine-learning
• Networking Stack from Scratch 21 April 2026

  TCP/IP, RIP, UDP, and DNS implementations in Go, supporting file transmission of up to 1 GB across networks of up to 8 virtual machines. Extended with a fully RFC-compliant SSH implementation (2,000+ additional lines) supporting sustained sessions of arbitrary length.

  tech
• Speculative Reluctance 15 April 2026

  AI labs are likely deliberately reluctant to scale because they are aware that any imminient shift to locally run models as the norm would render their compute redundant. We take Anthropic as a principal case study to validate this hypothesis.

  aitechspeculativeopen
• Ozymandias: A Static Site Framework 12 April 2026

  Ozymandias is the static site framework underlying this website, now extracted and released under the MIT license. It is a full-featured Hakyll and Pandoc setup for long-form writing: sidenotes, epistemic profiles, backlinks, wikilinks, a swipeable score reader, a semantic search pipeline, and more — configurable from a single YAML file and deployable with a single make command.

  metaprojectsreleases
• Beyond Comorbidity Indices 9 April 2026

  A deep learning model using ICD-10-CM diagnosis codes with a permutation-invariant Deep Sets aggregator improved 30-day unplanned readmission (AUC 0.7496 vs 0.6553 for CCI) and 30-day postdischarge in-hospital mortality (AUC 0.8557 vs 0.7844 for age-adjusted CCI) compared with Charlson and Elixhauser comorbidity-index benchmarks in a national claims database of over 113 million adult hospitalizations.

  researchresearch/machine-learning
• Where Does SIMD Help Post-Quantum Cryptography? A Micro-Architectural Study of ML-KEM on x86 AVX2 4 April 2026

  We systematically decompose the sources of SIMD speedup for ML-KEM (Kyber) on Intel x86-64 AVX2. By benchmarking four compilation variants, we demonstrate that GCC’s auto-vectorizer provides negligible benefit, and that hand-written AVX2 assembly delivers a $35\times$–$56\times$ performance increase for core arithmetic operations. This drives an end-to-end KEM speedup of $5.4\times$–$7.1\times$.

  researchresearch/cryptographyresearch/hpcresearch/compilersresearch/systemstechtech/hpctech/asmtech/C
• Empirical Musings on Spaced Repetition for Learning Beyond Memorization 26 March 2026

  A compendium of years of informal, empirical experiments aimed at extending the efficacy of Anki beyond rote memorization to more intricate levels of learning.

  nonfictionresearchresearch/informalmiscellany
• The Philosophical Legacy of Dostoevsky's Implicit Rejection of Logic and Science in Part I of Notes from Underground 24 October 2025

  Notes from Underground is widely admired as a cornerstone of literature, culture, and philosophy. This paper develops the argument that the primary philosophical undercurrent is a rejection of logic and science as end-alls in modern life, traced through comparison with the more explicitly articulated works of Dostoevsky’s contemporaries and successors: Nietzsche, Heidegger, Shestov, Ellul, Sartre, Camus, Husserl, and Arendt.

  nonfictionnonfiction/philosophy