6 papers
Characterizing Bias in Post-Bandit Inference under Index Algorithms
Lisu Wang, Yilun Chen, Jiaqi Lu
Bandit algorithms generate data for downstream inference, but adaptive sampling biases post-bandit sample means. We analyze this bias for stable index algorithms, including UCB1 an…
Bandit Allocational Instability
Yilun Chen, Jiaqi Lu
When multi-armed bandit (MAB) algorithms allocate pulls among competing arms, the resulting allocation can exhibit huge variation. This is particularly harmful in modern applicatio…
AC^0[p]-Frege Cannot Efficiently Prove that Constant-Depth Algebraic Circuit Lower Bounds are Hard
Jiaqi Lu, Rahul Santhanam, Iddo Tzameret
We study whether lower bounds against constant-depth algebraic circuits computing the Permanent over finite fields (Limaye-Srinivasan-Tavenas, J. ACM 2025; Forbes, CCC 2024) are ha…
Lower Bounds against the Ideal Proof System in Finite Fields
Tal Elbaz, Nashlen Govindasamy, Jiaqi Lu +1
Lower bounds against strong algebraic proof systems and specifically fragments of the Ideal Proof System (IPS), have been obtained in an ongoing line of work. All of these bounds,…
A characterization of sample adaptivity in UCB data
Yilun Chen, Jiaqi Lu
We characterize a joint CLT of the number of pulls and the sample mean reward of the arms in a stochastic two-armed bandit environment under UCB algorithms. Several implications of…
Tetragonal BaCoO: A Co Ferromagnetic Mott Insulator with Inverted Spin Crossover
Mingyu Xu, Haozhe Wang, Krishna Prasad Koirala +13
The interplay between crystal electric field splitting of d states and Hund's rule exchange energy in cobalt-based perovskites offers a promising avenue for inducing spin-state tra…