题目:
利用矩阵求逆引理,证明(10.32)和(10.33)。提示:首先证明(10.33)然后利用它来证明(10.32)
解答:
由(10.28)和(10.29)得到了贝叶斯一般线性模型的均值和方差:
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其中,线性关系满足:
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上述两个均值和方差,存在另外一种形式,即(10.32)和(10.33):
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这两个公式转换,在(12.26)(12.27)也存在,因此证明非常有意义。
另外,对于是列向量的情况,(10.33)计算也更加方便。
介绍矩阵求逆引理,即:
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证明参考:
https://blog.csdn.net/yihaizhiyan/article/details/6084383
因此,套用上述公式,得到:
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因此,(10.33)与(10.29)一致
接下来观察(10.32)中的:
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如果定义:
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那么:
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上面证明的最后第二步,又用了矩阵求逆引理,因此:
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最终带入后,得到:
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也就是10.32与10.28一致。