scholarly journals Gröbner bases for complex Grassmann manifolds

2011 ◽  
Vol 90 (104) ◽  
pp. 23-46 ◽  
Author(s):  
Branislav Prvulovic

By Borel?s description, integral cohomology of the complex Grassmann manifold Gk,n is a polynomial algebra modulo a well-known ideal. A strong Gr?bner basis for this ideal is obtained when k = 2 and k = 3.

2018 ◽  
Vol 68 (1) ◽  
pp. 181-196 ◽  
Author(s):  
Prateep Chakraborty ◽  
Shreedevi K. Masuti

AbstractLetGn,kdenote the complex Grassmann manifold ofk-dimensional vector subspaces of ℂn. Assumel,k≤ ⌊n/2⌋. We show that, for sufficiently largen, any continuous maph:Gn,l→Gn,kis rationally null homotopic if (i) 1 ≤k<l, (ii) 2 < l <k< 2(l− 1), (iii) 1 < l <k,ldividesnbutldoes not dividek.


2016 ◽  
Vol 66 (5) ◽  
Author(s):  
Marko Radovanović

AbstractThe mod 2 cohomology of the real flag manifolds is known to be isomorphic to a polynomial algebra modulo a certain ideal. In this paper reduced Gröbner bases for these ideals are obtained in the case of manifolds


2016 ◽  
Vol 99 (113) ◽  
pp. 31-42 ◽  
Author(s):  
Manuela Muzika-Dizdarevic ◽  
Marinko Timotijevic ◽  
Rade Zivaljevic

Conway and Lagarias observed that a triangular region T(m) in a hexagonal lattice admits a signed tiling by three-in-line polyominoes (tribones) if and only if m 2 {9d?1, 9d}d2N. We apply the theory of Gr?bner bases over integers to show that T(m) admits a signed tiling by n-in-line polyominoes (n-bones) if and only if m 2 {dn2 ? 1, dn2}d2N. Explicit description of the Gr?bner basis allows us to calculate the ?Gr?bner discrete volume? of a lattice region by applying the division algorithm to its ?Newton polynomial?. Among immediate consequences is a description of the tile homology group for the n-in-line polyomino.


1981 ◽  
Vol 24 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Samuel A. Ilori

If an oriented manifold M immerses in codimension k, then the normal bundle has dimension k such that its Euler class χ є Hk(M; Z) and χ2 є H2k(M; Z). (Cf. (3)).If M is the complex Grassmann manifold G2(Cn) of 2-planes in Cn (n = 4, 5,…, 15, 17), then dim M = 4n – 8 ≡ d and we shall show that although M immerses in R2d–1 by classical results (3), M does not immerse in Rd+d/2.The same result was obtained for n = 4 and 5 by Connell (2) and for n = 6 and 7 by the author (6). The nonimmersion results of this paper are new for n = 8, 9, …, 15, 17 and they are an improvement over the result for the general G2(Cn) obtained in (5). In this paper, we use generators of the cohomology ring of G2(Cn) different from those used in (2) and (6) and this simplifies the calculations considerably.


2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Pekka Kosunen

It is well known that the sum of points of the period-five cycle of the quadratic polynomial fc(x)=x2+c is generally not one-valued. In this paper we will show that the sum of cycle points of the curves of period five is at most three-valued on a new coordinate plane and that this result is essentially the best possible. The method of our proof relies on a implementing Gröbner-bases and especially extension theory from the theory of polynomial algebra.


2012 ◽  
Vol 12 (03) ◽  
pp. 1250182
Author(s):  
ZORAN Z. PETROVIĆ ◽  
BRANISLAV I. PRVULOVIĆ

The knowledge of cohomology of a manifold has shown to be quite relevant in various investigations: the question of vector fields, immersion and embedding dimension, and recently even in topological robotics. The method of Gröbner bases is applicable when the cohomology of the manifold is a quotient of a polynomial algebra. The mod 2 cohomology of the real flag manifold F(n1, n2, …, nr) is known to be isomorphic to a polynomial algebra modulo a certain ideal. Reduced Gröbner bases for these ideals are obtained in the case of manifolds F(1, 1, …, 1, n) including the complete flag manifolds (n = 1).


2010 ◽  
Vol 153 (2) ◽  
pp. 363-396 ◽  
Author(s):  
Vladimir Dotsenko ◽  
Anton Khoroshkin
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