Remarks on some recent fixed point results on quaternion-valued metric spaces (Q1722247)

Summary: In [ibid. 2014, Article ID 258985, 9 p. (2014; Zbl 1469.54091)], \textit{A. El-Sayed Ahmed} et al. introduced the notion of quaternion-valued metric as a generalization of metric and proved a common fixed point theorem in the context of quaternion-valued metric space. In this paper, we will show that the quaternion-valued metric spaces are subspaces of cone metric spaces. Consequently, the fixed point results in such spaces can be derived as a consequence of the corresponding existing fixed point result in the setting cone metric spaces.