在這篇論文，我們將在自反的巴拿赫空間(reflexive Banach space)裡探討變分不等式$V(T,C)$的相關問題。其中我們所要處理的函數$T$是極大單調(maximal monotone)的多值函數，而限制區域$C$是一個閉凸集合。為了探討問題$V(T,C)$的穩定度(stability)，我們考慮一個含參數$a$及一非負實數$\epsilon$的變形問題$V(a)$。首先，我們先介紹五種關於變分不等式的解之穩定性(stability)及可解性(feasibility)，然後再證明他們之間的等價關係。更進一步，我們再提出兩個更強的結果，並建立這些性質的等價關係。只要$T$和$C$滿足一些適當的條件，例如$C \subset int (co D(T))$的條件下，我們將可得到這七個特性是等價的。

In this paper, we study the variational inequality problem $V(a)$, associated with a maximal monotone multifunction $T$ and a closed convex set $C$, involving a parameter $a$ and a nonnegative number $\epsilon$ in a reflexive Banach space. We first introduce five characterizations concerning stability and feasible existence for solutions and then establish the equivalent relationship between these conditions. Further, we propose two extremely strong characterizations of stability vaild whenever $T$ enjoys some weak forms of strictly monotone property with respect to $C$. In particular, under the condition $C \subset int (co D(T))$ , we prove that the seven given conditions are equivalent.