scholarly journals Cycle Class Maps and Birational Invariants

2020 ◽  
Author(s):  
Brendan Hassett ◽  
Yuri Tschinkel
Keyword(s):  
Cycle Class

scholarly journals Beilinson's Hodge Conjecture for Smooth Varieties

2013 ◽  
Vol 11 (2) ◽  
pp. 243-282 ◽  
Author(s):  
Rob de Jeu ◽  
James D. Lewis
Keyword(s):  
Projective Variety ◽  
Chow Group ◽  
Hodge Conjecture ◽  
Generic Point ◽  
Higher Chow Group ◽  
Cycle Class

AbstractLet U/ℂ be a smooth quasi-projective variety of dimension d, CHr (U,m) Bloch's higher Chow group, andclr,m: CHr (U,m) ⊗ ℚ → homMHS (ℚ(0), H2r−m (U, ℚ(r)))the cycle class map. Beilinson once conjectured clr,m to be surjective [Be]; however, Jannsen was the first to find a counterexample in the case m = 1 [Ja1]. In this paper we study the image of clr,m in more detail (as well as at the “generic point” of U) in terms of kernels of Abel-Jacobi mappings. When r = m, we deduce from the Bloch-Kato conjecture (now a theorem) various results, in particular that the cokernel of clm,m at the generic point is the same for integral or rational coefficients.

scholarly journals OBSTRUCTIONS TO ALGEBRAIZING TOPOLOGICAL VECTOR BUNDLES

2019 ◽  
Vol 7 ◽  
Author(s):  
A. ASOK ◽  
J. FASEL ◽  
M. J. HOPKINS
Keyword(s):  
Vector Bundle ◽  
Complex Manifold ◽  
Algebraic Variety ◽  
Vector Bundles ◽  
Necessary Condition ◽  
Chern Classes ◽  
Smooth Complex ◽  
Steenrod Operations ◽  
Complex Algebraic Variety ◽  
Cycle Class

Suppose $X$ is a smooth complex algebraic variety. A necessary condition for a complex topological vector bundle on $X$ (viewed as a complex manifold) to be algebraic is that all Chern classes must be algebraic cohomology classes, that is, lie in the image of the cycle class map. We analyze the question of whether algebraicity of Chern classes is sufficient to guarantee algebraizability of complex topological vector bundles. For affine varieties of dimension ${\leqslant}3$, it is known that algebraicity of Chern classes of a vector bundle guarantees algebraizability of the vector bundle. In contrast, we show in dimension ${\geqslant}4$ that algebraicity of Chern classes is insufficient to guarantee algebraizability of vector bundles. To do this, we construct a new obstruction to algebraizability using Steenrod operations on Chow groups. By means of an explicit example, we observe that our obstruction is nontrivial in general.

scholarly journals Computing Néron–Severi groups and cycle class groups

2015 ◽  
Vol 151 (4) ◽  
pp. 713-734 ◽  
Author(s):  
Bjorn Poonen ◽  
Damiano Testa ◽  
Ronald van Luijk
Keyword(s):  
Equivalence Classes ◽  
Class Groups ◽  
Tate Conjecture ◽  
Etale Cohomology ◽  
Numerical Equivalence ◽  
Étale Cohomology ◽  
Integral Variety ◽  
Cycle Class

Assuming the Tate conjecture and the computability of étale cohomology with finite coefficients, we give an algorithm that computes the Néron–Severi group of any smooth projective geometrically integral variety, and also the rank of the group of numerical equivalence classes of codimension $p$ cycles for any $p$.

Eigenvalues of single-cycle class-sums in the symmetric group

1992 ◽  
Vol 41 (1) ◽  
pp. 147-151 ◽  
Author(s):  
Ruben Pauncz ◽  
Jacob Katriel
Keyword(s):  
Symmetric Group ◽  
Single Cycle ◽  
Cycle Class

scholarly journals Upaya Meningkatkan Hasil Belajar PKn Melalui Model Pembelajaran Kooperatif Tipe Round Club Peserta Didik Kelas IVA SD Negeri 64/IV Kota Jambi

2019 ◽  
Vol 19 (2) ◽  
pp. 264
Author(s):  
Efda Iryanti
Keyword(s):  
Elementary School ◽  
Learning Outcomes ◽  
Learning Model ◽  
Class Action ◽  
Learning Activities ◽  
Design Activity ◽  
Teaching Learning ◽  
Test Result ◽  
Cycle Class ◽  
Class Iv

Research is backed by the fact that PKn is one of the lessons that are lacking in the hearts of learners. Because this learning is considered to be a difficult and boring lesson, it affects the low learning outcomes of learners. Based on observations that authors as teachers in elementary School 64/IV Jambi, especially class IV. A on PKn subjects that students ' learning outcomes are still low. Only 51.85% of learners reach the KKM 75. This study uses two-cycle class action research. Each cycle consists of four phases: design, activity and observation, reflection, and revision. The target of this research is class IV students. A in SD Negeri 64/IV Jambi City. Data obtained in the form of formative test result, observation sheet of teaching learning activities. From the results analysts gained that student learning results experienced an increase from the pre cycle until the II cycle, the pre-cycle (64.81%) With the submission of 51.85, Cycle I (72.41%), with 70.37 and cycle II (80.93%) With the 85.19 submission. The conclusion of this study is the cooperative learning Model of Round Club type can positively affect the outcome of students learning outcomes of class IV. A State Elementary School 64/IV Jambi City, and this learning model can be used as an alternative learning of PKn.

scholarly journals Penggunaan Alat Bantu Pembelajaran untuk Meningkatkan Gerak Dasar Lompat Tinggi Gaya Straddle pada Siswa Kelas VI Sekolah Dasar

2019 ◽  
Vol 4 (4) ◽  
pp. 433
Author(s):  
Basri Basri
Keyword(s):  
Elementary School ◽  
Action Research ◽  
Learning Process ◽  
Class Action ◽  
Assessment Process ◽  
Average Value ◽  
Learning Aids ◽  
Basic Motion ◽  
Cycle Class

<p><strong>Abstract:</strong> This study aims to determine the increase in the basic motion of the high jump straddle force using learning aids. The method used is a two-cycle class action research. Each cycle is carried out in the form of a mixed assessment process consisting of four stages, namely planning, implementing, observing, and reflecting. The target of the research is the students of class VI semester 11 of elementary school 020 Samarinda Ilir. Based on the results of the analysis there is an increase in the average value of students completeness from the pre-cycle (67.7), the first cycle (71.5) and the second (77.2). In addition, based on observations students look more interested so they can improve the learning process of high jump practice.</p><strong>Abstrak:</strong> Penelitian ini bertujuan untuk mengetahui peningkatan gerak dasar lompat tinggi gaya <em>straddle</em> menggunakan alat bantu pembelajaran. Metode yang digunakan merupakan penelitian tindakan kelas sebanyak dua siklus. Setiap siklus dilaksanakan dalam wujud proses pengkajian berdaur yang terdiri atas empat tahap, yakni perencanaan, pelaksanaan, observasi, dan refleksi. Sasaran penelitian adalah siswa kelas VI semester 11 Sekolah Dasar Negeri 020 Samarinda Ilir. Berdasarkan hasil analisis terdapat peningkatan nilai rata-rata ketuntasan siswa dari pra siklus (67.7), siklus pertama (71.5) dan kedua yakni (77.2). Selain itu, berdasarkan observasi siswa terlihat lebih tertarik sehingga dapat meningkatkan proses pembelajaran praktik lompat tinggi.

scholarly journals Meningkatkan Prestasi Belajar Siswa Mata Pelajaran PKn dengan Metode Role Playing di SDN IV Gunung Rajak

FONDATIA ◽  
2017 ◽  
Vol 1 (2) ◽  
pp. 1-21
Author(s):  
Ahmad Izzuddin
Keyword(s):  
Data Analysis ◽  
Civic Education ◽  
Role Playing ◽  
Average Value ◽  
Education Material ◽  
Teaching Aids ◽  
Learning Skill ◽  
Improve Student Achievement ◽  
Good Learning ◽  
Cycle Class

This classroom action research aims to improve student achievement by applying role playing method in civic education education material impact of globalization. There are several problems found in the field observation, among others, the low achievement of students in civic education learning (Civics) with several factors that influence, among others, from students, families, material understanding, teachers and the use of teaching aids. Furthermore, by using the role playing method, the writer found a good learning achievement change that is from the result of data analysis of student's learning skill in class, reaching the average value of cycle class I is 67,50 and on second cycle equal to 77,50 and increase as big as 10.00, with completeness level in cycle I equal to 65,55%. In the second cycle of 95.45% Achievement of power seraf in cycle I 73.82%, the second cycle of 79.52% so that an increase of 5.70%

scholarly journals Involutions of varieties and Rost’s degree formula

2018 ◽  
Vol 2018 (745) ◽  
pp. 231-252 ◽  
Author(s):  
Olivier Haution
Keyword(s):  
Algebraic Variety ◽  
Chow Group ◽  
Complete Variety ◽  
Arbitrary Characteristic ◽  
Cycle Class

Abstract To an algebraic variety equipped with an involution, we associate a cycle class in the modulo two Chow group of its fixed locus. This association is functorial with respect to proper morphisms having a degree and preserving the involutions. Specialising to the exchange involution of the square of a complete variety, we obtain Rost’s degree formula in arbitrary characteristic (this formula was proved by Rost and Merkurjev in characteristic not two).

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