Formal Verification of Zero-Knowledge Circuits

Zero-knowledge circuits are sets of equality constraints over arithmetic expressions interpreted in a prime field; they are used to encode computations in cryptographic zero-knowledge proofs. We make the following contributions to the problem of ensuring that a circuit correctly encodes a computation: a formal framework for circuit correctness; an ACL2 library for prime fields; an ACL2 model of the existing R1CS (Rank-1 Constraint Systems) formalism to represent circuits, along with ACL2 and Axe tools to verify circuits of this form; a novel PFCS (Prime Field Constraint Systems) formalism to represent hierarchically structured circuits, along with an ACL2 model of it and ACL2 tools to verify circuits of this form in a compositional and scalable way; verification of circuits, ranging from simple to complex; and discovery of bugs and optimizations in existing zero-knowledge systems.Comment: In Proceedings ACL2-2023, arXiv:2311.0837

Wealth transmission and inequality among hunter-gatherers

Journal ArticleWe report quantitative estimates of intergenerational transmission and population-wide inequality for wealth measures in a set of hunter-gatherer populations. Wealth is defined broadly as factors that contribute to individual or household well-being, ranging from embodied forms, such as weight and hunting success, to material forms, such as household goods, as well as relational wealth in exchange partners. Intergenerational wealth transmission is low to moderate in these populations but is still expected to have measurable influence on an individual's life chances. Wealth inequality (measured with Gini coefficients) is moderate for most wealth types, matching what qualitative ethnographic research has generally indicated (if not the stereotype of hunter-gatherers as extreme egalitarians). We discuss some plausible mechanisms for these patterns and suggest ways in which future research could resolve questions about the role of wealth in hunter-gatherer social and economic life

FAEIS – the Food and Agricultural Education Information System

The Food and Agricultural Education Information System (FAEIS) compiles nationwide higher education data for agriculture, forestry and natural resources and other related disciplines. Data include undergraduate and graduate student enrollment and degrees awarded, graduate placement, and faculty headcounts and salaries by rank and discipline. Recently FAEIS has partnered with the National Association of University Forest Resources Programs (NAUFRP) to meet reporting needs for the organization. FAEIS is used by the United States Department of Agriculture (USDA) in responding to Congressional inquiries to support higher education and related USDA programs. Higher education administrators use FAEIS data in recruiting and benchmarking students and faculty, as well as institutional planning, and regional and national comparisons. Faculty use FAEIS for USDA - NIFA grant proposals. This session will provide faculty and administrators an opportunity to review the features of FAEIS and to discuss future directions to support the data requirements from their programs. The presentation will include a demonstration of the FAEIS Report Builder, a fast, convenient, clear, easy to learn and use tool for generating reports from FAEIS data. The live demonstration will focus on trends in enrollment and degrees awarded in forestry and natural resources

Dark Before Light: Testing the Cosmic Expansion History through the Cosmic Microwave Background

The cosmic expansion history proceeds in broad terms from a radiation dominated epoch to matter domination to an accelerated, dark energy dominated epoch. We investigate whether intermittent periods of acceleration are possible in the early universe -- between Big Bang nucleosynthesis (BBN) and recombination and beyond. We establish that the standard picture is remarkably robust: observations of anisotropies in the cosmic microwave background exclude any extra period of accelerated expansion between 1 \leq z \lesssim 10^5 (corresponding to 5\times10^{-4}\ {\rm eV} \leq T \lesssim 25\ {\rm eV}).Comment: 7 pages, 5 figure

Searching for the 3.5 keV Line in the Stacked Suzaku Observations of Galaxy Clusters

We perform a detailed study of the stacked Suzaku observations of 47 galaxy clusters, spanning a redshift range of 0.01-0.45, to search for the unidentified 3.5 keV line. This sample provides an independent test for the previously detected line. We detect only a 2sigma-significant spectral feature at 3.5 keV in the spectrum of the full sample. When the sample is divided into two subsamples (cool-core and non-cool core clusters), cool-core subsample shows no statistically significant positive residuals at the line energy. A very weak (2sigma-confidence) spectral feature at 3.5 keV is permitted by the data from the non-cool core clusters sample. The upper limit on a neutrino decay mixing angle from the full Suzaku sample is consistent with the previous detections in the stacked XMM-Newton sample of galaxy clusters (which had a higher statistical sensitivity to faint lines), M31, and Galactic Center at a 90% confidence level. However, the constraint from the present sample, which does not include the Perseus cluster, is in tension with previously reported line flux observed in the core of the Perseus cluster with XMM-Newton and Suzaku.Comment: ApJ in press, 9 pages, 3 figure

Crystal structure of Li3Ga(BO3)2

The crystal structure of trilithium gallium bis(orthoborate), Li3Ga(BO3)2, is isotypic with Li3Al(BO3)2 in a triclinic cell in space-group type P1. The three Li and the unique Ga atom are coordinated by four O atoms each in tetrahedra, and the two B atoms are coordinated by three O atoms in orthoborate triangles. Chains with composition [Ga2(BO3)4] 6 extend along the a axis. The Li atoms interleave these chains in tetrahedral interstices. A comparison is made between the structure model of the title compound and that of a previously reported model for a compound with the same composition [Abdullaev & Mamedov (1972). Zh. Strukt. Khim. 13, 943–946.

Liquid-Liquid Phase Separation in an Elastic Network

Living and engineered systems rely on the stable coexistence of two interspersed liquid phases. Yet surface tension drives their complete separation. Here we show that stable droplets of uniform and tuneable size can be produced through arrested phase separation in an elastic matrix. Starting with an elastic polymer network swollen by a solvent mixture, we change the temperature or composition to drive demixing. Droplets nucleate and grow to a stable size that is tuneable by the network cross-linking density, the cooling rate, and the composition of the solvent mixture. We discuss thermodynamic and mechanical constraints on the process. In particular, we show that the threshold for macroscopic phase separation is altered by the elasticity of the polymer network, and we highlight the role of internuclear correlations in determining the droplet size and polydispersity. This phenomenon has potential applications ranging from colloid synthesis and structural colour to phase separation in biological cells.Comment: 6 figure