Table. 2. Table 2

⋆	0	a	b	c
0	0	0	0	0
a	0	a	a	0
b	0	a	b	c
c	0	0	c	c

Kyungpook Mathematical Journal 2020;60:839~851 https://doi.org/10.5666/KMJ.2020.60.4.839

© KYUNGPOOK Math. J.