推 kemowu :2 direct sum 06/16 20:52
推 jacky7987 :1. If ab=0,a,b are not zero a=aba=0*a=0 這樣嗎 06/16 22:05
推 jacky7987 :不對別理上面那句... 06/16 22:08
→ empty24 :if ac=0->a(b+c)a=a->c=0 06/16 22:26
推 JohnMash :empty24 is right 06/16 22:45
1.
Let R be a ring with more than one element such that for each nonzero element
a in R, there is a unique b in R such that aba=a.
Show that "R has no zero divisors"
2.
Given an example of a nonzero homomorphism f:R->S of rings with identity
such that f(1_R)≠1_S
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