Mirror Symmetry and Algebraic Geometry, 1999 67 A
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Chapter 13 the Geometry of Circles
Chapter 13 TheR. Connelly geometry of circles Math 452, Spring 2002 Math 4520, Fall 2017 CLASSICAL GEOMETRIES So far we have been studying lines and conics in the Euclidean plane. What about circles, 14. The geometry of circles one of the basic objects of study in Euclidean geometry? One approach is to use the complex numbersSo far .we Recall have thatbeen the studying projectivities lines and of conics the projective in the Euclidean plane overplane., whichWhat weabout call 2, circles, Cone of the basic objects of study in Euclidean geometry? One approachC is to use CP are given by 3 by 3 matrices, and these projectivities restricted to a complex projective the complex numbers 1C. Recall that the projectivities of the projective plane over C, line,v.rhich which we wecall call Cp2, a CPare, given are the by Moebius3 by 3 matrices, functions, and whichthese projectivities themselves correspondrestricted to to a 2-by-2 matrices.complex Theprojective Moebius line, functions which we preservecall a Cpl the, are cross the Moebius ratio. This functions, is where which circles themselves come in. correspond to a 2 by 2 matrix. The Moebius functions preserve the cross ratio. This is 13.1where circles The come cross in. ratio for the complex field We14.1 look The for anothercross ratio geometric for the interpretation complex field of the cross ratio for the complex field, or better 1 yet forWeCP look= Cfor[f1g another. Recall geometric the polarinterpretation decomposition of the cross of a complexratio for numberthe complexz = refield,iθ, where r =orjz betterj is the yet magnitude for Cpl = ofCz U, and{ 00 } .Recallθ is the the angle polar that decomposition the line through of a complex 0 and znumbermakes with thez real -rei9, axis. -
Algebraic Geometry Michael Stoll
Introductory Geometry Course No. 100 351 Fall 2005 Second Part: Algebraic Geometry Michael Stoll Contents 1. What Is Algebraic Geometry? 2 2. Affine Spaces and Algebraic Sets 3 3. Projective Spaces and Algebraic Sets 6 4. Projective Closure and Affine Patches 9 5. Morphisms and Rational Maps 11 6. Curves — Local Properties 14 7. B´ezout’sTheorem 18 2 1. What Is Algebraic Geometry? Linear Algebra can be seen (in parts at least) as the study of systems of linear equations. In geometric terms, this can be interpreted as the study of linear (or affine) subspaces of Cn (say). Algebraic Geometry generalizes this in a natural way be looking at systems of polynomial equations. Their geometric realizations (their solution sets in Cn, say) are called algebraic varieties. Many questions one can study in various parts of mathematics lead in a natural way to (systems of) polynomial equations, to which the methods of Algebraic Geometry can be applied. Algebraic Geometry provides a translation between algebra (solutions of equations) and geometry (points on algebraic varieties). The methods are mostly algebraic, but the geometry provides the intuition. Compared to Differential Geometry, in Algebraic Geometry we consider a rather restricted class of “manifolds” — those given by polynomial equations (we can allow “singularities”, however). For example, y = cos x defines a perfectly nice differentiable curve in the plane, but not an algebraic curve. In return, we can get stronger results, for example a criterion for the existence of solutions (in the complex numbers), or statements on the number of solutions (for example when intersecting two curves), or classification results. -
1 Lecture 1 2 Lecture 2
1 Lecture 1 Possible Topics: 1. Hodge Conjecture. Probably about 5 lectures. 2. Geometric Langlands. Perhaps 5 lectures, and might contain geometry of derived categories 3. Geometry of Derived Categories 4. Grothendieck-Riemann-Roch? Maybe 2 lectures 5. Mirror Symmetry/Calabi-Yau's. As many lectures as needed. 2 Lecture 2 Geometric Langlands Program. Rather than describe the program right out, we will discuss examples first. This is essentially a nonabelian phenomenon. Input: A curve (smooth, compact, genus g) C and G a reductive group. Examples of reductive groups are GL(n); SL(n); SO(n); Sp(n), products, etc. Baby case: Abelian Geometric Langlands Conjecture. We have G = (C∗)r, and will take r = 1. This will roughly correspond to Class Field Theory in Number Theory, and the full GLC corresponds to nonabelian class field theory. Roughly we have objects G-bundles versus G local systems. In the case G = GL(n), we have that a G-bundle is a rank n vector bundle and a G-local system is a homomorphism π1(C) ! G which is the same as a rank n vector bundle with a flat connection. (All connections are flat, because curvature is a 2-form, and we are on a 1-dimensional object) 1 The moduli of rank n vector bundles is H (C; GLn(O)) = Bun and the 1 moduli space of G-local systems is H (C; GLn(C)) = Loc. 1 We know both that TV Bun = H (C; EndO (V )) and that T(V;r)Loc = 1 H (C; EndC(V )). We want to compute these dimensions, and we will use Riemann-Roch: h0 − h1(V ⊗ V ∗) = deg −rank(g − 1). -
Topics in Complex Analytic Geometry
version: February 24, 2012 (revised and corrected) Topics in Complex Analytic Geometry by Janusz Adamus Lecture Notes PART II Department of Mathematics The University of Western Ontario c Copyright by Janusz Adamus (2007-2012) 2 Janusz Adamus Contents 1 Analytic tensor product and fibre product of analytic spaces 5 2 Rank and fibre dimension of analytic mappings 8 3 Vertical components and effective openness criterion 17 4 Flatness in complex analytic geometry 24 5 Auslander-type effective flatness criterion 31 This document was typeset using AMS-LATEX. Topics in Complex Analytic Geometry - Math 9607/9608 3 References [I] J. Adamus, Complex analytic geometry, Lecture notes Part I (2008). [A1] J. Adamus, Natural bound in Kwieci´nski'scriterion for flatness, Proc. Amer. Math. Soc. 130, No.11 (2002), 3165{3170. [A2] J. Adamus, Vertical components in fibre powers of analytic spaces, J. Algebra 272 (2004), no. 1, 394{403. [A3] J. Adamus, Vertical components and flatness of Nash mappings, J. Pure Appl. Algebra 193 (2004), 1{9. [A4] J. Adamus, Flatness testing and torsion freeness of analytic tensor powers, J. Algebra 289 (2005), no. 1, 148{160. [ABM1] J. Adamus, E. Bierstone, P. D. Milman, Uniform linear bound in Chevalley's lemma, Canad. J. Math. 60 (2008), no.4, 721{733. [ABM2] J. Adamus, E. Bierstone, P. D. Milman, Geometric Auslander criterion for flatness, to appear in Amer. J. Math. [ABM3] J. Adamus, E. Bierstone, P. D. Milman, Geometric Auslander criterion for openness of an algebraic morphism, preprint (arXiv:1006.1872v1). [Au] M. Auslander, Modules over unramified regular local rings, Illinois J. -
Phylogenetic Algebraic Geometry
PHYLOGENETIC ALGEBRAIC GEOMETRY NICHOLAS ERIKSSON, KRISTIAN RANESTAD, BERND STURMFELS, AND SETH SULLIVANT Abstract. Phylogenetic algebraic geometry is concerned with certain complex projec- tive algebraic varieties derived from finite trees. Real positive points on these varieties represent probabilistic models of evolution. For small trees, we recover classical geometric objects, such as toric and determinantal varieties and their secant varieties, but larger trees lead to new and largely unexplored territory. This paper gives a self-contained introduction to this subject and offers numerous open problems for algebraic geometers. 1. Introduction Our title is meant as a reference to the existing branch of mathematical biology which is known as phylogenetic combinatorics. By “phylogenetic algebraic geometry” we mean the study of algebraic varieties which represent statistical models of evolution. For general background reading on phylogenetics we recommend the books by Felsenstein [11] and Semple-Steel [21]. They provide an excellent introduction to evolutionary trees, from the perspectives of biology, computer science, statistics and mathematics. They also offer numerous references to relevant papers, in addition to the more recent ones listed below. Phylogenetic algebraic geometry furnishes a rich source of interesting varieties, includ- ing familiar ones such as toric varieties, secant varieties and determinantal varieties. But these are very special cases, and one quickly encounters a cornucopia of new varieties. The objective of this paper is to give an introduction to this subject area, aimed at students and researchers in algebraic geometry, and to suggest some concrete research problems. The basic object in a phylogenetic model is a tree T which is rooted and has n labeled leaves. -
ROBERT L. FOOTE CURRICULUM VITA March 2017 Address
ROBERT L. FOOTE CURRICULUM VITA March 2017 Address/Telephone/E-Mail Department of Mathematics & Computer Science Wabash College Crawfordsville, Indiana 47933 (765) 361-6429 [email protected] Personal Date of Birth: December 2, 1953 Citizenship: USA Education Ph.D., Mathematics, University of Michigan, April 1983 Dissertation: Curvature Estimates for Monge-Amp`ere Foliations Thesis Advisor: Daniel M. Burns Jr. M.A., Mathematics, University of Michigan, April 1978 B.A., Mathematics, Kalamazoo College, June 1976 Magna cum Laude with Honors in Mathematics, Phi Beta Kappa, Heyl Science Scholarship Employment 1989–present, Wabash College Department Chair, 1997–2001, 2009–2012 Full Professor since 2004 Associate Professor, 1993–2004 Assistant Professor, 1991–1993 Byron K. Trippet Assistant Professor, 1989–1991 1983–1989, Texas Tech University, Assistant Professor (granted tenure) 1983, Kalamazoo College, Visiting Instructor 1976–1982, University of Michigan, Graduate Student Teaching Assistant 1976, 1977, The Upjohn Company, Mathematical Analyst Research Visits 2009, Korea Institute for Advanced Study (KIAS), Visiting Scholar Three weeks at the invitation of C. K. Han. 2009, Pennsylvania State Univ., Shapiro Visitor Four weeks at the invitation of Sergei Tabachnikov. 2008–2009, Univ. of Georgia, Visiting Scholar (sabbatical leave) 1996–1997, 2003–2004, Univ. of Illinois at Urbana Champaign, Visiting Scholar (sabbatical leave) 1991, Pohang Institute of Science and Technology, Pohang, Korea Three months at the invitation of C. K. Han. 1990, Texas Tech University Ten weeks at the invitation of Lance D. Drager. Current Fields of Interest Primary: Differential Geometry, Integral Geometry Professional Affiliations American Mathematical Society, Mathematical Association of America. Teaching Experience Graduate courses Differentiable manifolds, real analysis, complex analysis. -
VITA Sheldon Katz Urbana, IL 61801 Phone
VITA Sheldon Katz Urbana, IL 61801 Phone: (217) 265-6258 Education S.B. 1976 Massachusetts Institute of Technology (Mathematics) Ph.D. 1980 Princeton University (Mathematics) Professional Experience University of Illinois Professor 2001{ Dean's Special Advisor, College of LAS 2018{ Interim Chair, Department of Mathematics Fall 2017 Chair, Department of Mathematics 2006{2011 Oklahoma State University Regents Professor 1999{2002 Southwestern Bell Professor 1997{1999 Professor 1994{2002 Associate Professor 1989{1994 Assistant Professor 1987{1989 University of Oklahoma Assistant Professor (tenure 1987) 1984{1987 University of Utah Instructor 1980{1984 Visiting Positions MSRI Simons Visiting Professor 2018 Simons Center 2012 Mittag-Leffler Institute, Sweden Visiting Professor 1997 Duke University Visiting Professor 1991{1992 University of Bayreuth, West Germany Visiting Professor 1989 Institute for Advanced Study Member 1982{1983 Publications 1. Degenerations of quintic threefolds and their lines. Duke Math. Jour. 50 (1983), 1127{1135. 2. Lines on complete intersection threefolds with K=0. Math. Z. 191 (1986), 297{302. 3. Tangents to a multiple plane curve. Pac. Jour. Math. 124 (1986), 321{331. 4. On the finiteness of rational curves on quintic threefolds. Comp. Math. 60 (1986), 151{162. 5. Hodge numbers of linked surfaces in P4. Duke Math. Jour. 55 (1987), 89{95. 6. The cubo-cubic transformation of P3 is very special. Math. Z. 195 (1987), 255{257. 7. Iteration of Multiple point formulas and applications to conics. Proceed- ings of the Algebraic Geometry Conference, Sundance, UT 1986, SLN 1311, 147{155. 8. Varieties cut out by quadrics: Scheme theoretic versus homogeneous gen- eration of ideals (with L. -
Mirror Symmetry Is a Phenomenon Arising in String Theory in Which Two Very Different Manifolds Give Rise to Equivalent Physics
Clay Mathematics Monographs 1 Volume 1 Mirror symmetry is a phenomenon arising in string theory in which two very different manifolds give rise to equivalent physics. Such a correspondence has Mirror Symmetry Mirror significant mathematical consequences, the most familiar of which involves the enumeration of holomorphic curves inside complex manifolds by solving differ- ential equations obtained from a “mirror” geometry. The inclusion of D-brane states in the equivalence has led to further conjectures involving calibrated submanifolds of the mirror pairs and new (conjectural) invariants of complex manifolds: the Gopakumar Vafa invariants. This book aims to give a single, cohesive treatment of mirror symmetry from both the mathematical and physical viewpoint. Parts 1 and 2 develop the neces- sary mathematical and physical background “from scratch,” and are intended for readers trying to learn across disciplines. The treatment is focussed, developing only the material most necessary for the task. In Parts 3 and 4 the physical and mathematical proofs of mirror symmetry are given. From the physics side, this means demonstrating that two different physical theories give isomorphic physics. Each physical theory can be described geometrically, and thus mirror symmetry gives rise to a “pairing” of geometries. The proof involves applying R ↔ 1/R circle duality to the phases of the fields in the gauged linear sigma model. The mathematics proof develops Gromov-Witten theory in the algebraic MIRROR SYMMETRY setting, beginning with the moduli spaces of curves and maps, and uses localiza- tion techniques to show that certain hypergeometric functions encode the Gromov-Witten invariants in genus zero, as is predicted by mirror symmetry. -
Complex Analysis and Complex Geometry
Complex Analysis and Complex Geometry Finnur Larusson,´ University of Adelaide Norman Levenberg, Indiana University Rasul Shafikov, University of Western Ontario Alexandre Sukhov, Universite´ des Sciences et Technologies de Lille May 1–6, 2016 1 Overview of the Field Complex analysis and complex geometry form synergy through the geometric ideas used in analysis and an- alytic tools employed in geometry, and therefore they should be viewed as two aspects of the same subject. The fundamental objects of the theory are complex manifolds and, more generally, complex spaces, holo- morphic functions on them, and holomorphic maps between them. Holomorphic functions can be defined in three equivalent ways as complex-differentiable functions, convergent power series, and as solutions of the homogeneous Cauchy-Riemann equation. The threefold nature of differentiability over the complex numbers gives complex analysis its distinctive character and is the ultimate reason why it is linked to so many areas of mathematics. Plurisubharmonic functions are not as well known to nonexperts as holomorphic functions. They were first explicitly defined in the 1940s, but they had already appeared in attempts to geometrically describe domains of holomorphy at the very beginning of several complex variables in the first decade of the 20th century. Since the 1960s, one of their most important roles has been as weights in a priori estimates for solving the Cauchy-Riemann equation. They are intimately related to the complex Monge-Ampere` equation, the second partial differential equation of complex analysis. There is also a potential-theoretic aspect to plurisubharmonic functions, which is the subject of pluripotential theory. In the early decades of the modern era of the subject, from the 1940s into the 1970s, the notion of a complex space took shape and the geometry of analytic varieties and holomorphic maps was developed. -
Chapter 2 Affine Algebraic Geometry
Chapter 2 Affine Algebraic Geometry 2.1 The Algebraic-Geometric Dictionary The correspondence between algebra and geometry is closest in affine algebraic geom- etry, where the basic objects are solutions to systems of polynomial equations. For many applications, it suffices to work over the real R, or the complex numbers C. Since important applications such as coding theory or symbolic computation require finite fields, Fq , or the rational numbers, Q, we shall develop algebraic geometry over an arbitrary field, F, and keep in mind the important cases of R and C. For algebraically closed fields, there is an exact and easily motivated correspondence be- tween algebraic and geometric concepts. When the field is not algebraically closed, this correspondence weakens considerably. When that occurs, we will use the case of algebraically closed fields as our guide and base our definitions on algebra. Similarly, the strongest and most elegant results in algebraic geometry hold only for algebraically closed fields. We will invoke the hypothesis that F is algebraically closed to obtain these results, and then discuss what holds for arbitrary fields, par- ticularly the real numbers. Since many important varieties have structures which are independent of the field of definition, we feel this approach is justified—and it keeps our presentation elementary and motivated. Lastly, for the most part it will suffice to let F be R or C; not only are these the most important cases, but they are also the sources of our geometric intuitions. n Let A denote affine n-space over F. This is the set of all n-tuples (t1,...,tn) of elements of F. -
18.782 Arithmetic Geometry Lecture Note 1
Introduction to Arithmetic Geometry 18.782 Andrew V. Sutherland September 5, 2013 1 What is arithmetic geometry? Arithmetic geometry applies the techniques of algebraic geometry to problems in number theory (a.k.a. arithmetic). Algebraic geometry studies systems of polynomial equations (varieties): f1(x1; : : : ; xn) = 0 . fm(x1; : : : ; xn) = 0; typically over algebraically closed fields of characteristic zero (like C). In arithmetic geometry we usually work over non-algebraically closed fields (like Q), and often in fields of non-zero characteristic (like Fp), and we may even restrict ourselves to rings that are not a field (like Z). 2 Diophantine equations Example (Pythagorean triples { easy) The equation x2 + y2 = 1 has infinitely many rational solutions. Each corresponds to an integer solution to x2 + y2 = z2. Example (Fermat's last theorem { hard) xn + yn = zn has no rational solutions with xyz 6= 0 for integer n > 2. Example (Congruent number problem { unsolved) A congruent number n is the integer area of a right triangle with rational sides. For example, 5 is the area of a (3=2; 20=3; 41=6) triangle. This occurs iff y2 = x3 − n2x has infinitely many rational solutions. Determining when this happens is an open problem (solved if BSD holds). 3 Hilbert's 10th problem Is there a process according to which it can be determined in a finite number of operations whether a given Diophantine equation has any integer solutions? The answer is no; this problem is formally undecidable (proved in 1970 by Matiyasevich, building on the work of Davis, Putnam, and Robinson). It is unknown whether the problem of determining the existence of rational solutions is undecidable or not (it is conjectured to be so). -
Download Enumerative Geometry and String Theory Free Ebook
ENUMERATIVE GEOMETRY AND STRING THEORY DOWNLOAD FREE BOOK Sheldon Katz | 206 pages | 31 May 2006 | American Mathematical Society | 9780821836873 | English | Providence, United States Enumerative Geometry and String Theory Chapter 2. The most accessible portal into very exciting recent material. Topological field theory, primitive forms and related topics : — Nuclear Physics B. Bibcode : PThPh. Bibcode : hep. As an example, consider the torus described above. Enumerative Geometry and String Theory standard analogy for this is to consider a multidimensional object such as a garden hose. An example is the red circle in the figure. This problem was solved by the nineteenth-century German mathematician Hermann Schubertwho found that there are Enumerative Geometry and String Theory 2, such lines. Once these topics are in place, the connection between physics and enumerative geometry is made with the introduction of topological quantum field theory and quantum cohomology. Enumerative Geometry and String Theory mirror symmetry relationship is a particular example of what physicists call a duality. Print Price 1: The book contains a lot of extra material that was not included Enumerative Geometry and String Theory the original fifteen lectures. Increasing the dimension from two to four real dimensions, the Calabi—Yau becomes a K3 surface. This problem asks for the number and construction of circles that are tangent to three given circles, points or lines. Topological Quantum Field Theory. Online Price 1: Online ISBN There are infinitely many circles like it on a torus; in fact, the entire surface is a union of such circles. For other uses, see Mirror symmetry. As an example, count the conic sections tangent to five given lines in the projective plane.