Eivind Dahl
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 Jun18 comment What happens geometrically when the Jacobson radical is non-zero? Naturally I do not think there is actually anything wrong with it. I removed the comment on separation; oops. I also tweaked the question, since we're not actually looking at the ring of real-valued functions on an affine scheme. I'm looking for intuition, and phenomena which can be directly attributed to a non-vanishing Jacobson radical $J$. How does for instance the space $Spec(A/J)$ look compared to $Spec(A)$. Hopefully the question is in better shape now. Thanks for the feedback! Jun18 revised What happens geometrically when the Jacobson radical is non-zero? deleted 47 characters in body Jun18 comment What happens geometrically when the Jacobson radical is non-zero? Old habit from writing mails, but I might as well stop if anyone feels it worth commenting on. Jun18 asked What happens geometrically when the Jacobson radical is non-zero? Jun13 comment etale space v. covering space So covering map $\Leftrightarrow$ étale map? This is a surprise to me. I think my attempts to locally trivialize an arbitrary étale map rely on tacit assumptions. Jun11 comment How to study math to really understand it and have a healthy lifestyle with free time? I'd try to get an overview of whatever I'm learning first. I'd like to think of it as a big canvas; fill in the details according to whatever piques your interest. You absolutely positively can't learn everything (not even close), but you can learn top-down instead of bottom-up. For your comments on rigour, you might find this interesting: cheng.staff.shef.ac.uk/morality/morality.pdf May28 asked What is the universal property of the tangent bundle of a smooth manifold? May25 comment Is there a universal property of $\text{Spec}(-)$? Exactly; thank you! May25 accepted Is there a universal property of $\text{Spec}(-)$? May25 comment Is there a universal property of $\text{Spec}(-)$? I clarified this assumption in the OP. May25 revised Is there a universal property of $\text{Spec}(-)$? added 34 characters in body May25 comment Is there a universal property of $\text{Spec}(-)$? I knew about that, but I'm thinking about $\text{Spec}$ as a functor $\text{Ring}^{op}\to\text{LRSpaces}$. This question may still be silly though :) May25 asked Is there a universal property of $\text{Spec}(-)$? May19 answered Soft Question - Intuition of the meaning of homology groups May7 revised Is there a noetherification of locally noetherian schemes? deleted 111 characters in body May4 revised Is there a noetherification of locally noetherian schemes? deleted 48 characters in body; edited body May4 asked Is there a noetherification of locally noetherian schemes? Apr28 comment Natural Isomorphism $\mbox{Hom}(\oplus_\alpha A_\alpha,G) \simeq \prod_\alpha \mbox{Hom}(A_\alpha,G)$ @Qwirk: That's precicely what happens in this case as well, but with different words in it. By definition, a morphism from the coproduct is the same thing as a morphism from each of its factors. Apr25 answered The $d$ in Leibniz's Notation Apr25 revised Usage of dx in Integrals added 1 characters in body