publications

2025

1. Asymptotic mutual information in quadratic estimation problems over compact groups

   Kaylee Y Yang, Timothy LH Wee, and Zhou Fan

   Information and Inference: A Journal of the IMA, 2025

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   Motivated by applications to group synchronization and quadratic assignment on random data, we study a general problem of Bayesian inference of an unknown “signal” belonging to a high-dimensional compact group, given noisy pairwise observations of a featurization of this signal. We establish a quantitative comparison between the signal-observation mutual information in any such problem with that in a simpler model with linear observations, using interpolation methods. For group synchronization, our result proves a replica formula for the asymptotic mutual information and Bayes-optimal mean-squared-error. Via analyses of this replica formula, we show that the conjectural phase transition threshold for computationally-efficient weak recovery of the signal is determined by a classification of the real-irreducible components of the observed group representation(s), and we fully characterize the information-theoretic limits of estimation in the example of angular/phase synchronization over \mathbbSO(2)/\mathbbU(1). For quadratic assignment, we study observations given by a kernel matrix of pairwise similarities and a randomly permutated and noisy counterpart, and we show in a bounded signal-to-noise regime that the asymptotic mutual information coincides with that in a Bayesian spiked model with i.i.d. signal prior.

   @article{yang2024asymptotic,
     author = {Yang, Kaylee Y and Wee, Timothy LH and Fan, Zhou},
     title = {Asymptotic mutual information in quadratic estimation problems over compact groups},
     journal = {Information and Inference: A Journal of the IMA},
     volume = {14},
     number = {3},
     pages = {iaaf024},
     year = {2025},
     issn = {2049-8772},
     doi = {10.1093/imaiai/iaaf024},
     url = {https://doi.org/10.1093/imaiai/iaaf024},
     eprint = {https://academic.oup.com/imaiai/article-pdf/14/3/iaaf024/63893336/iaaf024.pdf}
   }

2. Random projections beyond zero overlap

   Timothy LH Wee, and Sekhar Tatikonda

   Electronic Journal of Probability, to appear, 2025

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   A random vector whose norm and overlap (inner product with an independent copy) concentrates is shown to have random low-dimensional projections that are approximately random Gaussians. Conversely, asymptotically random Gaussian projections imply these hypotheses. This extends and unites several existing results in geometric functional analysis and spin glasses. Applications include a large-system characterization of the joint law of cavity fields in the Sherrington-Kirkpatrick model.

   @article{wee2023random,
     title = {Random projections beyond zero overlap},
     author = {Wee, Timothy LH and Tatikonda, Sekhar},
     journal = {Electronic Journal of Probability, to appear},
     year = {2025},
   }

2023

1. Local independence in mean-field spin glasses

   Timothy LH Wee, and Sekhar Tatikonda

   arXiv preprint arXiv:2212.14851, 2023

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   We present a new approach to local independence in spin glasses, i.e. the phenomenon that any fixed subset of coordinates is asymptotically independent in the thermodynamic limit. The approach generalizes the rigorous cavity method from Talagrand by considering multiple cavity sites. Under replica-symmetric conditions of thin-shell and overlap concentration, the cavity fields are revealed to be asymptotically independent, conditionally on the disorder, which in turn leads to local independence. Conversely, it is shown that local independence implies those replica-symmetric properties. The framework is general enough to encompass the classical and soft spin ([-1,1]) Sherrington-Kirkpatrick models, as well as the Gardner spin glasses.

   @article{wee2022local,
     title = {Local independence in mean-field spin glasses},
     author = {Wee, Timothy LH and Tatikonda, Sekhar},
     journal = {arXiv preprint arXiv:2212.14851},
     year = {2023},
   }

2. 1182: Fluid resuscitation with crystalloids plus colloids versus crystalloids alone in septic shock

   Mahmoud Ammar, Abdalla Ammar, Russel Roberts, Jen-Ting Tina Chen, Timothy LH Wee, and Shamsuddin Akhtar

   Critical Care Medicine, 2023

   Bib HTML

   @article{ammar20231182,
     title = {1182: Fluid resuscitation with crystalloids plus colloids versus crystalloids alone in septic shock},
     author = {Ammar, Mahmoud and Ammar, Abdalla and Roberts, Russel and Chen, Jen-Ting Tina and Wee, Timothy LH and Akhtar, Shamsuddin},
     journal = {Critical Care Medicine},
     volume = {51},
     number = {1},
     pages = {589},
     year = {2023},
     publisher = {LWW},
   }

2022

1. Relationship between glucose time-in-range in diabetic and non-diabetic patients and mortality in critically ill patients

   Mahmoud A Ammar, Abdalla A Ammar, Timothy LH Wee, Ranjit Deshpande, Matthew Band, and Shamsuddin Akhtar

   Journal of Intensive Care Medicine, 2022

   Bib HTML

   @article{ammar2022relationship,
     title = {Relationship between glucose time-in-range in diabetic and non-diabetic patients and mortality in critically ill patients},
     author = {Ammar, Mahmoud A and Ammar, Abdalla A and Wee, Timothy LH and Deshpande, Ranjit and Band, Matthew and Akhtar, Shamsuddin},
     journal = {Journal of Intensive Care Medicine},
     volume = {37},
     number = {12},
     pages = {1625--1633},
     year = {2022},
     publisher = {SAGE Publications Sage CA: Los Angeles, CA},
   }