Not an algebraist myself, but this is interesting. Few things I do know: Read ------------------------------- Quickly think of algebraically closed field --------- $\mathbb C$ abelian group ---------------------- $(\mathbb R;+)$ non-abelian group ----------------- $(\operatorname{SO}(n,\mathbb R);\times)$ ; ($n>2$) simple group ----------------------- $(A_n; \circ)$ ; ($n\ge5$)