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This article is cited in 2 scientific papers (total in 2 papers)
An estimate of the dimension of the null spaces of linear superpositions
B. L. Fridman
Abstract:
In this article it is proved that for continuously differentiable functions $f_1(x,y),f_2(x,y),\dots,f_n(x,y)$ a region $U$ of the $x$, $y$ plane can be found such that the dimension of the space of vectors $(\varphi_1(t),\dots,\varphi_n(t))$ for which $\sum_{i=1}^n\varphi_i(f_i(x,y))=0$ in $U$, where $\varphi_i(t)\in L_2$, either equals infinity or else does not exceed the number $(n-1)n/2$. Superpositions of the form $\sum_{i=1}^n\psi_i(f_i(x,y))$ are also shown to be closed and nowhere dense in $L_2$.
Bibliography: 3 titles.
Received: 25.06.1969
Citation:
B. L. Fridman, “An estimate of the dimension of the null spaces of linear superpositions”, Math. USSR-Sb., 11:1 (1970), 101–114
Linking options:
https://www.mathnet.ru/eng/sm3439https://doi.org/10.1070/SM1970v011n01ABEH002064 https://www.mathnet.ru/eng/sm/v124/i1/p111
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