Abstract
It is proved that there exists a weak Armendriz ring R over which the polynomial ring R[x] is not weak Armendariz. This answers an open question of Liu and Zhao in 2006 in the negative, and eliminates the misunderstanding of the question having a positive solution by Hashemi in 2008.
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ACKNOWLEDGMENTS
The author would like to express his gratitude to Professor A. Smoktunowicz for her helpful suggestions. This work is supported by the Natural Foundation of Shandong Province in China (Y2008A04, ZR2010AM003, and BS2010SF017).
Notes
Communicated by A. Smoktunowicz.