On the regularity and stability of three-phase-lag thermoelastic plate

In this paper we consider the following three-phase-lag thermoelastic plate: ρu¨=−Δ(μΔu−mθ),c(θ˙+τqθ¨)=mΔ(u˙+τqu¨)+Δ(k∗α+τν∗θ+kτθθ˙).We obtain analyticity and exponential stability for associated C0-semigroup when coefficients satisfy τν≥k∗τq. The of semigroup still holds τν<k∗τq. However, instability solution was proved by Routh–Hurwitz rule.