We investigate the inverse q-numerical range of $$2\times 2$$ matrices. A quartic curve is formulated that generates unit vectors for the inverse q-numerical range according to Tsing’s circle formula. Properties of this quartic curve are discussed and corresponding examples are described.

中文翻译：

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生成 2×2 矩阵的逆 q 数值范围的曲线

我们研究了 $$2\times 2$$ 矩阵的逆 q 数值范围。制定了四次曲线，根据 Tsing 的圆公式生成逆 q 数值范围的单位向量。讨论了该四次曲线的特性并描述了相应的示例。