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Letter from Chris Bennett to Emmett L. Bennett Jr., November 07, 1998
No full textChris Bennett updates Bennett on his current job prospects.Classic
Photo of Margaret Bennett, Dale Jarvis, and Chris Mouland at a MUNFLA 50th anniversary event.
No full textPhoto of MUN folklore alumnis Margaret Bennett and Dale Jarvis with MUNFLA (MUN Folklore and Language Archive) archival assistant Chris Mouland at a MUNFLA 50th anniversary event
Improved Hardness of BDD and SVP Under Gap-(S)ETH
No full textWe show improved fine-grained hardness of two key lattice problems in the _p norm: Bounded Distance Decoding to within an α factor of the minimum distance (BDD_{p, α}) and the (decisional) γ-approximate Shortest Vector Problem (GapSVP_{p,γ}), assuming variants of the Gap (Strong) Exponential Time Hypothesis (Gap-(S)ETH). Specifically, we show:
1) For all p ∈ [1, ∞), there is no 2^{o(n)}-time algorithm for BDD_{p, α} for any constant α > α_kn, where α_kn = 2^{-c_kn} < 0.98491 and c_kn is the ₂ kissing-number constant, unless non-uniform Gap-ETH is false.
2) For all p ∈ [1, ∞), there is no 2^{o(n)}-time algorithm for BDD_{p, α} for any constant α > α^‡_p, where α^‡_p is explicit and satisfies α^‡_p = 1 for 1 ≤ p ≤ 2, α^‡_p 2, and α^‡_p → 1/2 as p → ∞, unless randomized Gap-ETH is false.
3) For all p ∈ [1, ∞) ⧵ 2 ℤ and all C > 1, there is no 2^{n/C}-time algorithm for BDD_{p, α} for any constant α > α^†_{p, C}, where α^†_{p, C} is explicit and satisfies α^†_{p, C} → 1 as C → ∞ for any fixed p ∈ [1, ∞), unless non-uniform Gap-SETH is false.
4) For all p > p₀ ≈ 2.1397, p ∉ 2ℤ, and all C > C_p, there is no 2^{n/C}-time algorithm for GapSVP_{p, γ} for some constant γ > 1, where C_p > 1 is explicit and satisfies C_p → 1 as p → ∞, unless randomized Gap-SETH is false.
Our results for BDD_{p, α} improve and extend work by Aggarwal and Stephens-Davidowitz (STOC, 2018) and Bennett and Peikert (CCC, 2020). Specifically, the quantities α_kn and α^‡_p (respectively, α^†_{p,C}) significantly improve upon the corresponding quantity α_p^* (respectively, α_{p,C}^*) of Bennett and Peikert for small p (but arise from somewhat stronger assumptions). In particular, Item 1 improves the smallest value of α for which BDD_{p, α} is known to be exponentially hard in the Euclidean norm (p = 2) to an explicit constant α < 1 for the first time under a general-purpose complexity assumption. Items 1 and 3 crucially use the recent breakthrough result of Vlăduţ (Moscow Journal of Combinatorics and Number Theory, 2019), which showed an explicit exponential lower bound on the lattice kissing number. Finally, Item 4 answers a natural question left open by Aggarwal, Bennett, Golovnev, and Stephens-Davidowitz (SODA, 2021), which showed an analogous result for the Closest Vector Problem
Too Much Information piece commenting on the local media scene. Author Chris B
No full textToo Much Information piece commenting on the local media scene. Author Chris Barry analyzes WGME-13\u27s inclusion of promotions for network entertainment in its news broadcasts; discusses the bi-weekly interviews of former governor Angus King on National Public Radio\u27s Marketplace; and praises Ed King\u27s West End News for its high quality
Hardness of Bounded Distance Decoding on Lattices in _p Norms
No full textBounded Distance Decoding BDD_{p,α} is the problem of decoding a lattice when the target point is promised to be within an α factor of the minimum distance of the lattice, in the _p norm. We prove that BDD_{p, α} is NP-hard under randomized reductions where α → 1/2 as p → ∞ (and for α = 1/2 when p = ∞), thereby showing the hardness of decoding for distances approaching the unique-decoding radius for large p. We also show fine-grained hardness for BDD_{p,α}. For example, we prove that for all p ∈ [1,∞) ⧵ 2ℤ and constants C > 1, ε > 0, there is no 2^((1-ε)n/C)-time algorithm for BDD_{p,α} for some constant α (which approaches 1/2 as p → ∞), assuming the randomized Strong Exponential Time Hypothesis (SETH). Moreover, essentially all of our results also hold (under analogous non-uniform assumptions) for BDD with preprocessing, in which unbounded precomputation can be applied to the lattice before the target is available.
Compared to prior work on the hardness of BDD_{p,α} by Liu, Lyubashevsky, and Micciancio (APPROX-RANDOM 2008), our results improve the values of α for which the problem is known to be NP-hard for all p > p₁ ≈ 4.2773, and give the very first fine-grained hardness for BDD (in any norm). Our reductions rely on a special family of "locally dense" lattices in _p norms, which we construct by modifying the integer-lattice sparsification technique of Aggarwal and Stephens-Davidowitz (STOC 2018)
Hardness of the (Approximate) Shortest Vector Problem: A Simple Proof via Reed-Solomon Codes
No full textWe give a simple proof that the (approximate, decisional) Shortest Vector Problem is NP-hard under a randomized reduction. Specifically, we show that for any p ≥ 1 and any constant γ < 2^{1/p}, the γ-approximate problem in the _p norm (γ-GapSVP_p) is not in RP unless NP ⊆ RP. Our proof follows an approach pioneered by Ajtai (STOC 1998), and strengthened by Micciancio (FOCS 1998 and SICOMP 2000), for showing hardness of γ-GapSVP_p using locally dense lattices. We construct such lattices simply by applying "Construction A" to Reed-Solomon codes with suitable parameters, and prove their local density via an elementary argument originally used in the context of Craig lattices.
As in all known NP-hardness results for GapSVP_p with p < ∞, our reduction uses randomness. Indeed, it is a notorious open problem to prove NP-hardness via a deterministic reduction. To this end, we additionally discuss potential directions and associated challenges for derandomizing our reduction. In particular, we show that a close deterministic analogue of our local density construction would improve on the state-of-the-art explicit Reed-Solomon list-decoding lower bounds of Guruswami and Rudra (STOC 2005 and IEEE Transactions on Information Theory 2006).
As a related contribution of independent interest, we also give a polynomial-time algorithm for decoding n-dimensional "Construction A Reed-Solomon lattices" (with different parameters than those used in our hardness proof) to a distance within an O(√log n) factor of Minkowski’s bound. This asymptotically matches the best known distance for decoding near Minkowski’s bound, due to Mook and Peikert (IEEE Transactions on Information Theory 2022), whose work we build on with a somewhat simpler construction and analysis
Manzanar camp map, "Manzanar, a photograph essay"
No full textA map of "Manzanar Relocation Center" reproduced from "Manzanar pilgrimage program" by hand by Chris S. Uyemura. The caption reads, "General plan of the W.R.A. Camp at Manzanar, California. Chris Uyemura Collection." A page from: Manzanar, a photograph essay (csudh_uye_0001).The Chris S. Uyemura Manzanar Photograph Collection consists of a pictorial essay, “Manzanar, a photographic essay,” and additional loose photos, which were compiled and collected by Chris S. Uyemura. The essay contains photographs, texts, and newspaper clippings, and was submitted to Professor Donald T. Hata of the Department of History at CSU Dominguez Hills. The collection depicts the incarceration of people of Japanese ancestry in the Manzanar camp during World War II as well as reflects the events, contrasting with photographs of the Manznar National Historic Site, which illustrates what is left of the camp today. The collection was originally named as “Asian Pacific Studies Collection Box 14.
John and Chris Crutcher Folder
No full text2 pages of family history documents containing and related to John Crutcher; Chris Crutcher - including: News articles; Valley clerk; Author; obi
Prisoner voting for the final general election before release is a solution that balances concerns about democratic rights
No full textDemocratic Audit has recently featured analysis of prisoner voting rights from several leading experts. In the second of two new contributions to this debate – following Peter Ramsay’s earlier post – Chris Bennett and Daniel Viehoff argue that both sides of the debate can make strong claims to democratic principles. They make a new proposal that aims to balance these competing concerns
Intimacy Unguarded: Chris Kraus
No full textThe Central Saint Martins research project 'Intimacy Unguarded', run by Emma Talbot and Dr Jo Morra, hosted a visit to Central Saint Martins by United States author Chris Kraus. Kraus is a highly respected writer (I Love Dick, Summer of Hate, Aliens and Anorexia etc) and editor of the semi-texte series 'Native Agents'. In this event, Kraus gave a reading from 'I Love Dick' and was then interviewed by Emma Talbot, to a live public audience.
'Intimacy Unguarded' also ran a seminar called 'Write A Letter To Chris Kraus'. Mirroring the format for the celebrated book 'I Love Dick', in which Kraus uses the letter as a way of addressing a particular figure (with whom she is obsessed) whilst simultaneously unpacking her own personal thoughts and research, participants were invited to 'Write a Letter To Chris Kraus'.
Chris Kraus was present at the seminar, where letters were read aloud and Kraus was the first respondent. Those taking part were from Raven Row, CSM BAFA, MAFA and Afterall. An excerpt from Kraus's book and a selection of the letters will be published in the June 2017n issue of Journal of Visual Art Practice, to be guest-edited by Talbot and Morra
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