Sheaf theory | Complex manifolds

Exponential sheaf sequence

In mathematics, the exponential sheaf sequence is a fundamental short exact sequence of sheaves used in complex geometry. Let M be a complex manifold, and write OM for the sheaf of holomorphic functions on M. Let OM* be the subsheaf consisting of the non-vanishing holomorphic functions. These are both sheaves of abelian groups. The exponential function gives a sheaf homomorphism because for a holomorphic function f, exp(f) is a non-vanishing holomorphic function, and exp(f + g) = exp(f)exp(g). Its kernel is the sheaf 2πiZ of locally constant functions on M taking the values 2πin, with n an integer. The exponential sheaf sequence is therefore The exponential mapping here is not always a surjective map on sections; this can be seen for example when M is a punctured disk in the complex plane. The exponential map is surjective on the stalks: Given a germ g of an holomorphic function at a point P such that g(P) ≠ 0, one can take the logarithm of g in a neighborhood of P. The long exact sequence of sheaf cohomology shows that we have an exact sequence for any open set U of M. Here H0 means simply the sections over U, and the sheaf cohomology H1(2πiZ|U) is the singular cohomology of U. One can think of H1(2πiZ|U) as associating an integer to each loop in U. For each section of OM*, the connecting homomorphism to H1(2πiZ|U) gives the winding number for each loop. So this homomorphism is therefore a generalized winding number and measures the failure of U to be contractible. In other words, there is a potential topological obstruction to taking a global logarithm of a non-vanishing holomorphic function, something that is always locally possible. A further consequence of the sequence is the exactness of Here H1(OM*) can be identified with the Picard group of holomorphic line bundles on M. The connecting homomorphism sends a line bundle to its first Chern class. (Wikipedia).

Video thumbnail

Algebra Ch 46: Exponential Function (1 of 12) What is an Exponential Function?

Visit http://ilectureonline.com for more math and science lectures! To donate: http://www.ilectureonline.com/donate https://www.patreon.com/user?u=3236071 We will learn an exponential function is a function in the form of f(x)=b^x where b=base (b(greater than)0, and b does not=1) and x=e

From playlist THE "WHAT IS" PLAYLIST

Video thumbnail

Exponential Notation

http://mathispower4u.wordpress.com/

From playlist Polynomial Operations

Video thumbnail

Schemes 3: exactness and sheaves

This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne. In it we discuss exactness of morphisms of sheaves over a topological space.

From playlist Algebraic geometry II: Schemes

Video thumbnail

Finding the sum or an arithmetic series using summation notation

👉 Learn how to find the partial sum of an arithmetic series. A series is the sum of the terms of a sequence. An arithmetic series is the sum of the terms of an arithmetic sequence. The formula for the sum of n terms of an arithmetic sequence is given by Sn = n/2 [2a + (n - 1)d], where a is

From playlist Series

Video thumbnail

From Cohomology to Derived Functors by Suresh Nayak

PROGRAM DUALITIES IN TOPOLOGY AND ALGEBRA (ONLINE) ORGANIZERS: Samik Basu (ISI Kolkata, India), Anita Naolekar (ISI Bangalore, India) and Rekha Santhanam (IIT Mumbai, India) DATE & TIME: 01 February 2021 to 13 February 2021 VENUE: Online Duality phenomena are ubiquitous in mathematics

From playlist Dualities in Topology and Algebra (Online)

Video thumbnail

Solving an exponential equation using the one to one property 16^x + 2 = 6

👉 Learn how to solve exponential equations. An exponential equation is an equation in which a variable occurs as an exponent. To solve an exponential equation, we isolate the exponential part of the equation. Then we take the log of both sides. Note that the base of the log should correspo

From playlist Solve Exponential Equations with Logarithms

Video thumbnail

Étale cohomology - 10/15/2020

Artin comparison, intro to pi_1

From playlist Étale cohomology and the Weil conjectures

Video thumbnail

Schemes 39: Divisors and Dedekind domains

This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne. In this lecture we describe Weil and Cartier divisors for Dedekind domains, showing that they correspond to the two classical ways of defining the class group

From playlist Algebraic geometry II: Schemes

Video thumbnail

Finding the rule of the sequence using multiplication and addition

👉 Learn how to write the explicit formula for the nth term of an arithmetic sequence. A sequence is a list of numbers/values exhibiting a defined pattern. A number/value in a sequence is called a term of the sequence. An arithmetic sequence is a sequence in which each term of the sequence

From playlist Sequences

Video thumbnail

Étale cohomology 9/15/2020

Čech cohomology part II, Čech-to-derived spectral sequence, Mayer-Vietoris, étale cohomology of quasi-coherent sheaves, the Artin-Schreier exact sequence and the étale cohomology of F_p in characteristic p.

From playlist Étale cohomology and the Weil conjectures

Video thumbnail

Rahul Pandharipande - Enumerative Geometry of Curves, Maps, and Sheaves 1/5

The main topics will be the intersection theory of tautological classes on moduli space of curves, the enumeration of stable maps via Gromov-Witten theory, and the enumeration of sheaves via Donaldson-Thomas theory. I will cover a mix of classical and modern results. My goal will be, by th

From playlist 2021 IHES Summer School - Enumerative Geometry, Physics and Representation Theory

Video thumbnail

What is the definition of an arithmetic sequence

👉 Learn about sequences. A sequence is a list of numbers/values exhibiting a defined pattern. A number/value in a sequence is called a term of the sequence. There are many types of sequence, among which are: arithmetic and geometric sequence. An arithmetic sequence is a sequence in which

From playlist Sequences

Video thumbnail

Lecture 11: Sheaves form a topos (Part 2)

In this talk Patrick Elliott proves that the category of sheaves on a site is a topos, by discussing the exponentials and subobject classifier in detail. The notes are already online: The lecture notes are available here: http://therisingsea.org/notes/ch2018-lecture11.pdf. For the genera

From playlist Topos theory seminar

Video thumbnail

Grothendieck-Serre Duality by Suresh Nayak

PROGRAM DUALITIES IN TOPOLOGY AND ALGEBRA (ONLINE) ORGANIZERS: Samik Basu (ISI Kolkata, India), Anita Naolekar (ISI Bangalore, India) and Rekha Santhanam (IIT Mumbai, India) DATE & TIME: 01 February 2021 to 13 February 2021 VENUE: Online Duality phenomena are ubiquitous in mathematics

From playlist Dualities in Topology and Algebra (Online)

Video thumbnail

Learn the basics for solve an exponential equation using a calculator

👉 Learn how to solve exponential equations. An exponential equation is an equation in which a variable occurs as an exponent. To solve an exponential equation, we isolate the exponential part of the equation. Then we take the log of both sides. Note that the base of the log should correspo

From playlist Solve Exponential Equations with Logarithms

Related pages

Complex geometry | Winding number | Mathematics | Chern class | Holomorphic function | Integer | Exponential function | Kernel (algebra) | Sheaf cohomology | Locally constant function | Logarithm | Sheaf (mathematics) | Abelian group | Picard group | Complex manifold