Levi Neuwirth

• Index-Period Normal Forms for Monoid-Aggregated Recursive Summaries 16 May 2026

  A monoid-aggregated summary evaluates a finite rooted cop-labeled tree bottom-up through a finite state set and a finite commutative child-aggregation monoid. Once the multiplicity observation map and the monoid are fixed, context equivalence has finite index and is exactly equality of a finite behavior vector. This note sharpens the resulting pumping and normal-form theory: the crude pigeonhole bound in the product monoid is replaced by an exact index–period bound on each behavior type’s child contribution, isolating support, modular, and saturation counting in the Boolean, cyclic, and threshold families. Combining exact sibling pumping with a size-minimality argument — no behavior vector may repeat along a root-to-leaf path — yields a finite universe of normal representatives, and an external tie-break selects one canonical representative per class. Worked computations for one-node trees, stars, unary chains, and split-versus-concentrated examples make the bounds concrete.

  researchresearch/mathematicsresearch/algebraresearch/graph-theory
• Branch-Based Local Capture in Tree-Ball Geometry: Sharp Positive and Negative Results 6 May 2026

  We study a local team-chase problem in a $d$-regular graph whose ball of large radius around the robber is a tree. We isolate the right local invariant — the deep load along a nonbacktracking path tube — and prove a coordinated package of positive and negative results: (i) sharp counts of geodesic cones and their truncations, (ii) a one-round universal branch-persistence lemma, (iii) a $t$-round generalization with depth budget $2t+1$, (iv) a sampling barrier showing that any proof relying on the path-tube certificate requires $\Omega((d-1)^{t-1} \cdot t)$ cops, and (v) a finite-order potential-degeneration barrier showing that any local invariant depending only on order-$r$ tube data is strictly insufficient to certify even $(r+1)$-round persistence. Together, these results form a double pincer: certifying $t$-round persistence by an order-$r$ local invariant requires $r \geq t$, and order-$t$ resolution requires $\Omega((d-1)^{t-1})$ cops to occupy by uniform sampling. This rules out order-$r$ branch-aggregated potentials (for any fixed $r$) as a route to $\Theta(\log n)$-round chase from polylogarithmic cops, and identifies the precise structural reason why the natural iteration of the one-round argument fails.

  researchresearch/mathematicsresearch/graph-theory
• 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