**Authors:** Nader Jafari Rad

### Abstract

The paper [1] has one main theorem, namely Theorem 3. In the last
line of the theorem’s proof it is assumed that the set S ∗ is independent.
This assumption is not necessarily correct, and it is not possible to fix
it, since the set S is randomly chosen. This mistake makes the main
result of the paper wrong.
At the request of the author (Received October 21, 2019), the article
has been retracted.

Department of Mathematics, Shahed University

Tehran, Iran

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