- #1
mathmari
Gold Member
MHB
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Hey! ![Eek! :eek: :eek:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Let $R$ be a commutative ring with unity and $a,b\in R$ with $a$ invertible.
I want to show that the mapping $x\rightarrow ax+b$ defines a unique automorphism of $R[x]$ that is idempotent in $R$. Could you give me a hint what I am supposed to do? (Wondering)
Let $R$ be a commutative ring with unity and $a,b\in R$ with $a$ invertible.
I want to show that the mapping $x\rightarrow ax+b$ defines a unique automorphism of $R[x]$ that is idempotent in $R$. Could you give me a hint what I am supposed to do? (Wondering)