這篇論文是探討 2×2 矩陣之單位數值半徑球，首先學習數值半徑的計算，利用單式矩陣，任意的 2×2 矩陣可轉成上三角矩陣，對於單位數值半徑球，我們可以正出其具有 convex 的特性，對於2×2 上三角矩陣其數值半徑小於等於 1 的條件是可獲得的 This thesis is to explore the numerical radius unit ball for 2×2 matrix. The computation of the radius for the 2×2 matrix are studied first. By using the unitary matrix, any 2×2 matrix can be transferred into the upper-triangular form. For the numerical radius unit ball, we can prove that it is convex. For the 2×2 upper-triangular matrices that the condition such that the numerical radius w(A) ? 1 is derived.
