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JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb., 1991 Volume 182, Number 10, Pages 1379–1392 (Mi sm1378)

On the representation of functions as a sum of several compositions

V. A. Medvedev


Abstract: Let $\varphi_i$ be continuous mappings of a compactum $X$ onto compacta $Y_i$, $i=1,\dots,n$. The following theorem is known for $n=2$: if any bounded function $f$ on $X$ can be represented in the form $f=g_1\circ\varphi_1+g_2\circ\varphi_2$, where $g_1$ and $g_2$ are bounded functions on $Y_1$ and $Y_2$, then any continuous $f$ can be represented in the same form with continuous $g_1$ and $g_2$. An example is constructed showing that the analogous theorem is false for $n>2$.

UDC: 517.948

MSC: 54C05

Received: 24.04.1990


 English version:
Mathematics of the USSR-Sbornik, 1993, 74:1, 119–130

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