For the given sample points , and matrix formed by covariance function with sample points as parameters , when the number of sample points approaches infinite , it is proven that this matrix spectrum will approach the spectral approach theorem for positive - definite kernel of integral equation 對給定的樣本點(diǎn),由樣本點(diǎn)為變量的協(xié)方差函數(shù)構(gòu)成的矩陣,當(dāng)樣本點(diǎn)個(gè)數(shù)趨于無窮大時(shí),證明此矩陣譜逼近于積分方程正定核的譜逼近定理。