We study approximation by arbitrary linear combinations of $n$ translates of a single function of periodic functions. We construct some linear methods of this approximation for univariate functions in the class induced by the convolution with a single function, and prove upper bounds of the $L^p$-approximation convergence rate by these methods, when $n \to \infty$, for $1 \leq p \leq \infty$. We also generalize these results to classes of multivariate functions defined the convolution with the tensor product of a single function. In the case $p=2$, for this class, we also prove a lower bound of the quantity characterizing best approximation of by arbitrary linear combinations of $n$ translates of arbitrary function.
翻译:我们用任意的线性组合来研究周期函数单一函数的近似值,即一美元,我们研究周期函数的单一函数的任意线性组合。我们为一个函数的组合引发的类别中的单项函数构建了某种近似值的线性方法,并用这些方法证明美元到美元,即美元到美元时的美元接近率的上限值。我们还将这些结果推广到多种函数的类别中,这些函数定义了与单一函数的发声产物的相交。在这样的例子中,美元=2美元,对于这一类别,我们也证明以任意函数的美元任意线性组合为最佳近似值的上限值较低。