Waterloo Research: Recent submissions
Now showing items 61-80 of 2464
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On Specht's Theorem in UHF C*-algebras
(Elsevier, 2021-01-01)Specht’s Theorem states that two matrices Aand Bin Mn(C)are unitarily equivalent if and only if tr(w(A, A∗)) =tr(w(B, B∗))for all words w(x, y)in two non-commuting variables xand y. In this article we examine to what extent ... -
Triangular Operator Algebras and Simultaneous Triangularisation
(American Mathematical Society, 2023)We consider the question of whether every collection of compact operators that is contained in a triangular operator algebra (in the sense of Kadison and Singer) must be simultaneously triangularisable. The answer is shown ... -
On Norm-Limits of Algebraic Quasidiagonal Operators
(Theta Foundation, 2020)It is still an open question to know whether or not every quasidiagonal operator can be expressed as a norm-limit of algebraic quasidiagonal operators. In this note, we provide an alternative characterization of those ... -
On the spectrum of the Sylvester-Rosenblum operator acting on triangular algebras
(Ele-Math, 2020)Let A and B be algebras and M be an A -B-bimodule. For A ∈ A , B ∈B, we define the Sylvester-Rosenblum operator τA,B :M →M via τA,B(M) = AM+MB for all M ∈ M . We investigate the spectrum of τA,B in three settings, namely: ... -
Expansion und Dynastische Politik in Pontos: Zwei neue Ären unter Pharnakes I.
(Steiner Verlag, Stuttgart, Germany, 2022-01-01)The most heated debates on early-Pontic history surround the treaty of alliance made between Pharnakes I and the citizens of Chersonesos in year 157 (IOSPE I2 402 = III3 103). About a half of the present generation of ... -
The Chronology of the Asylia Dossier from Kos Revisited in Light of Some Recent Epigraphic Discoveries
(Kabalcı, Istanbul, Türkiye, 2021-12-31)While the Third Syrian War was raging, the Koans deployed substantial diplomatic efforts to have the asylia of their Asklepieion and the panhellenic penteteric games recognized throughout the Mediterranean world. In the ... -
Cavitation threshold evaluation of porcine cerebrospinal fluid using a Polymeric Split Hopkinson Pressure Bar-Confinement chamber apparatus
(Elsevier, 2019-12)Studies investigating mild Traumatic Brain Injury (mTBI) in the military population using experimental head surrogates and Finite Element (FE) head models have demonstrated the existence of transient negative pressures ... -
Polynomial Bounds for Chromatic Number. IV: A Near-polynomial Bound for Excluding the Five-vertex Path
(Springer, 2023-09-15)A graph G is H -free if it has no induced subgraph isomorphic to H. We prove that a P5-free graph with clique number ω ≥ 3 has chromatic number at most ωlog2(ω). The best previous result was an exponential upper bound ... -
Pure Pairs. V. Excluding Some Long Subdivision.
(Springer, 2023-06-16)A \pure pair" in a graph G is a pair A;B of disjoint subsets of V (G) such that A is complete or anticomplete to B. Jacob Fox showed that for all " > 0, there is a comparability graph G with n vertices, where n is large, ... -
Strengthening Rodl's theorem
(Elsevier, 2023-11)What can be said about the structure of graphs that do not contain an induced copy of some graph H? Rödl showed in the 1980s that every H-free graph has large parts that are very sparse or very dense. More precisely, ... -
My data collection is complete, now what? Connecting researchers to Data Repositories that can support Cold Regions Researchers
(University of Waterloo, 2020-11-27)The natural climate variability of the cold regions, together with the relatively sparse observational data sets and difficult terrain can make data collection which supports key science challenging. Notwithstanding, ... -
Role of Artificial Intelligence in Theranostics: Toward Routine Personalized Radiopharmaceutical Therapies
(Elsevier, 2021-10)KEY POINTS AI has shown promising applications in quantitative imaging required for dosimetry. Segmentation of organs and tumors, the most time consuming task in the dosimetry workflow, can be automated using AI. ... -
Clinical Applications of Artificial Intelligence in positron emission tomography of Lung Cancer
(Elsevier, 2022-01)The ability of a computer to perform tasks normally requiring human intelligence or artificial intelligence (AI) is not new. However, until recently, practical applications in medical imaging were limited, especially in ... -
Induced subgraphs and tree decompositions II. Toward walls and their line graphs in graphs of bounded degree.
(Elsevier, 2024-01)This paper is motivated by the following question: what are the unavoidable induced subgraphs of graphs with large treewidth? Aboulker et al. made a conjecture which answers this question in graphs of bounded maximum ... -
Induced subgraphs and tree decompositions VII. Basic obstructions in H-free graphs.
(Elsevier, 2024-01)We say a class C of graphs is clean if for every positive integer t there exists a positive integer w(t) such that every graph in C with treewidth more than w(t) contains an induced subgraph isomorphic to one of the ... -
Planting Imagination: Community Co-Design for Chinatown Toronto | Impact Report
(University of Waterloo, 2023-07)Planting Imagination ran from April 2021 to March 2023 (during a pandemic recovery period) in Toronto’s Chinatown West neighbourhood. It brought together a group of local Chinatown community organizations and Toronto ... -
Analysis of the optimal time to withdraw investments from hedge funds with alternative fee structures
(Oxford Academic, 2022-04)We study the optimal stopping problem arising from an investor determining the optimal time to withdraw from a hedge fund investment with a shared loss fee structure and a positive fee for assets under management. The ... -
The Reinforcement Learning Kelly Strategy
(Taylor & Francis, 2022-03)The full Kelly portfolio strategy's deficiency in the face of estimation errors in practice can be mitigated by fractional or shrinkage Kelly strategies. This paper provides an alternative, the RL Kelly strategy, based on ... -
Mean-Expectile Portfolio Selection
(Springer, 2021)We consider a mean-expectile portfolio selection problem in a continuous-time diffusion model. We exploit the close relationship between expectiles and the Omega performance measure to reformulate the problem as the ... -
Lower Tail Independence of Hitting Times of Two-Dimensional Diffusions
(Cambridge University Press, 2018)The coefficient of tail dependence is a quantity that measures how extreme events in one component of a bivariate distribution depend on extreme events in the other component. It is well known that the Gaussian copula has ...