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W. Zhan
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[Edit: I have completely changed the question in response to the replies given]

I am curious if there is well defined notion of reduced $E_\infty$-ring.

Let $CAlg$ denote the $\infty$-categoorycategory of $E_\infty$-ring, $CAlg_1$, the one category of communicative rings. I would like to define the analog for reduced ring.

One categorically, $ CAlg_1^{red} \hookrightarrow CAlg_1$ admits a left adjoint $A \mapsto A^{red}:=A /nil(A)$.


We can define $$CAlg^{red} \hookrightarrow CAlg$$ as the $\infty$-cat. of $E_\infty$-rings whose underling ring is reduced.

Question: Does Does there exist a left adjoint? What about when we restrict to connective $E_\infty$-rings? As mentioned in comments by Marc, this is false.


It seems too me thatQuestion[Edit]: What should be the approoachnotion of $E_\infty$-ring? Harry in HA,7.2.3 is somewhat relevantthe comment says that this should be an ordinary reduced ring. I'd like to knowI would appreciate if thissome explanation could make this question is addressed somewhere in the literatureprecise.

I am curious if there is well defined notion of reduced $E_\infty$-ring.

Let $CAlg$ denote the $\infty$-categoory of $E_\infty$-ring, $CAlg_1$, the one category of communicative rings. I would like to define the analog for reduced ring.

One categorically, $ CAlg_1^{red} \hookrightarrow CAlg_1$ admits a left adjoint $A \mapsto A^{red}:=A /nil(A)$.


We can define $$CAlg^{red} \hookrightarrow CAlg$$ as the $\infty$-cat. of $E_\infty$-rings whose underling ring is reduced.

Question: Does there exist a left adjoint? What about when we restrict to connective $E_\infty$-rings?


It seems too me that the approoach in HA,7.2.3 is somewhat relevant. I'd like to know if this this question is addressed somewhere in the literature.

[Edit: I have completely changed the question in response to the replies given]

I am curious if there is well defined notion of reduced $E_\infty$-ring.

Let $CAlg$ denote the $\infty$-category of $E_\infty$-ring, $CAlg_1$, the one category of communicative rings. I would like to define the analog for reduced ring.

One categorically, $ CAlg_1^{red} \hookrightarrow CAlg_1$ admits a left adjoint $A \mapsto A^{red}:=A /nil(A)$.


We can define $$CAlg^{red} \hookrightarrow CAlg$$ as the $\infty$-cat. of $E_\infty$-rings whose underling ring is reduced. Does there exist a left adjoint? As mentioned in comments by Marc, this is false.


Question[Edit]: What should be the notion of $E_\infty$-ring? Harry in the comment says that this should be an ordinary reduced ring. I would appreciate if some explanation could make this precise.

Source Link
W. Zhan
  • 448
  • 2
  • 8

Is there a definition of reduced $E_\infty$ ring?

I am curious if there is well defined notion of reduced $E_\infty$-ring.

Let $CAlg$ denote the $\infty$-categoory of $E_\infty$-ring, $CAlg_1$, the one category of communicative rings. I would like to define the analog for reduced ring.

One categorically, $ CAlg_1^{red} \hookrightarrow CAlg_1$ admits a left adjoint $A \mapsto A^{red}:=A /nil(A)$.


We can define $$CAlg^{red} \hookrightarrow CAlg$$ as the $\infty$-cat. of $E_\infty$-rings whose underling ring is reduced.

Question: Does there exist a left adjoint? What about when we restrict to connective $E_\infty$-rings?


It seems too me that the approoach in HA,7.2.3 is somewhat relevant. I'd like to know if this this question is addressed somewhere in the literature.