Groups
Laws of Composition
1.1
for all \(a,b,c\in S\), we have \((ab)c = a = a(bc)\), therefore law of composition in \(S\) is associative.
Suppose \(e\) i as the identity, then for all \(a\in S\), we have \(ae=a=ea=e\), therefore \(S=\{e\}\)
1.2
1.3
for
标签：ab,updating,Solution,therefore,Martin,Exercise From： https://www.cnblogs.com/shinidetiehanhan/p/16708840.html