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I am reading Joseph J. Rotman's book: A First Course in Abstract Algebra with Applications (Third Edition) ...
I am currently studying Section 7.1 Prime Ideals and Maximal Ideals ... ...
I need help with understanding an aspect of the proof of Proposition 7.5
Proposition 7.5 and its proof reads as follows:View attachment 4727In the first part of the proof of the proposition above we read the following:
"Let $$I$$ be a prime ideal. Since $$I$$ is a proper idea, we have $$1 \notin I$$ and so $$1 + I \neq 0 + I$$ in $$R/I$$ ... ... ... "
My question is ... ... why is Rotman taking trouble to show that $$1 + I \neq 0 + I$$ in $$R/I$$?
What is the point Rotman is making ... ... ?
Hope someone can clarify this matter ... ...
Peter
I am currently studying Section 7.1 Prime Ideals and Maximal Ideals ... ...
I need help with understanding an aspect of the proof of Proposition 7.5
Proposition 7.5 and its proof reads as follows:View attachment 4727In the first part of the proof of the proposition above we read the following:
"Let $$I$$ be a prime ideal. Since $$I$$ is a proper idea, we have $$1 \notin I$$ and so $$1 + I \neq 0 + I$$ in $$R/I$$ ... ... ... "
My question is ... ... why is Rotman taking trouble to show that $$1 + I \neq 0 + I$$ in $$R/I$$?
What is the point Rotman is making ... ... ?
Hope someone can clarify this matter ... ...
Peter