About this article
Published Online: Dec 31, 2020
Page range: 35 - 38
Received: Jul 17, 2019
Accepted: Sep 23, 2019
DOI: https://doi.org/10.2478/aupcsm-2020-0003
Keywords
© 2020 Amir Sahami, published by Sciendo
This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License.
In this short note, we give some counter examples which show that [11, Proposition 3.5] is not true. As a consequence, the arguments in [11, Proposition 4.10] are not valid.