Personal notes

These are notes written for myself to better understand some papers/books and make comments to them. Use at your own risk.


0) Comments to: D. Arinkin, D. Gaitsgory, D. Kazhdan, S. Raskin, N. Rozenblyum, Y. Varshavsky, The stack of local systems with restricted variation and geometric Langlands theory with nilpotent singular support, arxiv version 2, and Duality for automorphic sheaves with nilpotent singular support, arxiv version 2

I try to give detailed explanations and justify certains things which were not clear to me (and were left to a reader) in the cited papers.


1) Assumptions on the sheaf theory for the small FLE paper.


2) Analog of the theta-sheaf on the 3-fold metaplectic cover of G_2? (last modified 10 Oct 2021)


3) My notes of Embryo GL seminar (organized by D. Gaitsgory) (last modified 5 Feb 2022)

Notes mostly about commutative factorization algebras.


4) Comments to Gaitsgory, The local and global versions of the Whittaker category  (last modified 4 September 2021)

 We give detailed explanations of many claims left to a reader in this paper.


5) Comments to D. Gaitsgory, S. Lysenko,  Parameters and duality for the metaplectic geometric Langlands theory

 We give some more detailed explanations of some points than those from the main text. (the latest corrected version of the paper itself is available here).


6)  Comments to Beilinson, Drinfeld, Chiral algebras, Colloquium Publications, vol. 51, 2004   (last modified 12 dec 2017)

   We develop to some extent the theory of chiral algebras for perverse sheaves. For example, we explain the existence of free chiral algebras and enveloping chiral algebras of Lie-* algebras in the setting of perverse sheaves.


7)  Comments to Rozenblyum, Gaitsgory, A Study in Derived Algebraic Geometry: Volumes I and II, Mathematical Surveys and Monographs
Volume: 221; 2017
  (last modified 25 July 2022, 250 pages)

  We prove many claims left for a reader in this book and some others used in practice. The latest corrected version of this book is found on Dennis Gaitsgory's homepage. Some notions from higher algebra are introduced and discussed in the model-independent setting, for example  oo-operads, relative undercategory construction, relative colimit, relative Kan extension, flat morphism of oo-categories. We also prove some claims of the derived algebraic geomery left to a reader in this book.


8)  Comments to Braverman, Gaitsgory, Deformations of Local Systems and Eisenstein Series, GAFA  2008, Vol. 17, Issue 6, 1788 - 1850  (last modified 18 Dec 2017)

  Many things are left for a reader to be worked out himself. We work out some of them.


9)  Comments to Feigin, Finkelberg, Kuznetsov, Mirković, Ivan Semi-infinite flags. II. Local and global intersection cohomology of quasimaps' spaces. Differential topology, infinite-dimensional Lie algebras, and applications, 113 - 148, Amer. Math. Soc. Transl. Ser. 2, 194, Adv. Math. Sci., 44, Amer. Math. Soc., Providence, RI, 1999  (last modified 23 dec 2017)

 We give a new proof of a result of this paper, which allows to avoid the theory of weights. This simplifies the definition of the action of the dual Lie algebra on the Eisenstein series corresponding to the trivial local system.


10) Comments to S. Raskin, Chiral categories (last modified 20 dec 2019)

We justify certain things left to a reader

Weakly multiplicative quasi-coherent sheaves (last modified 23 Nov 2019)

This note contains some examples of these objects introduced in Raskin, Chiral categories


11) Comment to Gaitsgory, Sheaves of categories and notion of 1-affineness (last modified 13 feb 2020)

We justify certain things left to a reader


12)  Comments to Krahmer, Notes on Koszul algebras  (last modified 29 Sept 2017)