Formal Groups Reading Notes

Tags: #reading_notes #my_talks #talk_notes #todo #reading_projects #stable_homotopy #blog

Formal Groups Reading Notes

Formal Groups and Spectra

Formal Groups

Basics

  • Motivation: why should one care about [[Formal group|formal groups]]?

    • Idea: substitute for Lie algebras in positive characteristic
    • Formal group and lie algebra carry the same info in char 0
    • Functor: LieGroups (or AlgGrp) → LieAlgebras factors through FormalGroups

    Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled.png

  • Motivation: if a formal group were for sale, why might you buy it?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 1.png

  • What is a formal group law?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 2.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 3.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 4.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 5.png

  • Why is the group law called “formal”?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 6.png

  • How “should” one think of a formal group?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 7.png

  • What is a formal exponential and formal logarithm?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 8.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 9.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 10.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 11.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 12.png

  • What are examples of formal groups? What is a morphism? When are they isomorphic?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 13.png

  • What are the additive and multiplicative formal groups?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 14.png

  • How are the additive and multiplicative formal groups related?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 15.png

  • What is the height of a formal group?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 16.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 17.png

  • How can one extend formal groups over R to R-algebras?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 18.png

  • What is the formal scheme interpretation of formal groups?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 19.png

  • How does iterated K-theory show up in the theory of formal groups?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 20.png

Other Connections to Elliptic Curves

  • What is the invariant differential of an elliptic curve?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 21.png

  • How does one extract the formal group of an elliptic curve using differential forms?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 22.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 23.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 24.png

  • What can a formal group tell you about your curve?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 25.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 26.png

Lazard Ring

  • What is the Lazard ring?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 27.png

  • What does it mean to be a “universal” coefficient ring?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 28.png

  • How exactly is the Lazard ring universal?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 29.png

  • How are formal groups related to spectra?

  • What is MU?

  • How are formal groups related to cobordism?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 30.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 31.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 32.png

  • How is the Lazard ring directly related to cobordism classification?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 33.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 34.png

Stable Homotopy

tmf

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 35.png

  • How is tmf defined in terms of the moduli stack of elliptic curves?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 36.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 37.png

K-Theories

  • How is the algebraic K-theory of a commutative ring defined/constructed in terms of monoidal categories?

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 38.png

Projects/Reading Notes/Formal_Groups_and_Spectra/attachments/Untitled 39.png

#reading_notes #my_talks #talk_notes #todo #reading_projects #stable_homotopy #blog