Definition talk:Center (Abstract Algebra)/Ring
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I think the group is not $R$, but $R^*$, to avoid finding an inverse for the zero under multiplication. -- Lord Farin
- No, anon edit was correct - only a group when R is a division ring. General field and it's only a semigroup. If anything, this question could be raised in the context of the "subgroup of units", perhaps.
- It also raises the question about whether it makes sense to discuss the cener of any general semigroup - well, it does look as though it can be described, but whether it makes any actual sense or yield any interesting results is a different question. For some semigroups it may indeed be empty. --prime mover 02:50, 31 October 2011 (CDT)