Timeline for Functorial multiplication on commutative rings
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 22, 2017 at 7:24 | vote | accept | Alexander Braverman | ||
| Dec 19, 2017 at 16:16 | answer | added | Tyler Lawson | timeline score: 15 | |
| Dec 19, 2017 at 14:14 | history | edited | Alexander Braverman | CC BY-SA 3.0 |
added 80 characters in body
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| Dec 19, 2017 at 14:14 | comment | added | Alexander Braverman | I forgot to say that unit remain a unit | |
| Dec 19, 2017 at 13:00 | comment | added | Olivier Bégassat | Given a ring define the bijection $\varphi:R\to R$ on the underlying set by imposing $\varphi(x)=-x$. Define a new ring structure $R^-$ on the underlying set $R$ by transfer of structure along $\varphi$. Addition is the same, but multiplication is given by $x\times^-x'=-xx'$. This should define a functor $C\to C$ where any morphism of commutative rings is sent to the same underlying set map. Since addition is the same, this functor commutes with the forgetful functor to abelian groups. Does this work ? | |
| Dec 19, 2017 at 12:43 | history | asked | Alexander Braverman | CC BY-SA 3.0 |