H. Hirai

activity

20242026

collaborators

5 papers

stat.ME2026

Interval Estimation of the Common Shape Parameter and Coefficient of Variation of Several Weibull Populations under Progressive Censoring

Bankitdor M. Nongrum, Adarsha Kumar Jena

The Weibull distribution is one of the most flexible continuous probability distributions used to model various failure rates and skewed data in reliability engineering, industry,…

math.OC2026

Gradient descent for unbounded convex functions on Hadamard manifolds and its applications to scaling problems

Hiroshi Hirai, Keiya Sakabe

In this paper, we study the asymptotic behavior of continuous- and discrete-time gradient flows of a ``lower-unbounded" convex function $f$ on a Hadamard manifold $M$ , particularly…

math.OC2026

Generalized gradient flows in Hadamard manifolds and convex optimization on entanglement polytopes

Hiroshi Hirai

In this paper, we address the optimization problem of minimizing $Q (d f_{x})$ over a Hadamard manifold $M$ , where $f$ is a convex function on $M$ , $d f_{x}$ is the differen…

math.OC2025

A scaling characterization of nc-rank via unbounded gradient flow

Hiroshi Hirai

Given a tuple of $n \times n$ complex matrices $A = (A_{1}, A_{2}, \dots, A_{m})$ , the linear symbolic matrix $A = A_{1} x_{1} + A_{2} x_{2} + \dots + A_{m} x_{m}$ is nonsingular in the noncomm…

cs.GT2024

Polyhedral Clinching Auctions for Indivisible Goods

Hiroshi Hirai, Ryosuke Sato

In this study, we propose the polyhedral clinching auction for indivisible goods, which has so far been studied for divisible goods. As in the divisible setting by Goel et al. (201…