On the angles between certain arithmetically defined subspaces of 𝐂 n

Robert Brooks

Annales de l'institut Fourier (1987)

  • Volume: 37, Issue: 1, page 175-185
  • ISSN: 0373-0956

Abstract

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If { v i } and { w j } are two families of unitary bases for C n , and θ is a fixed number, let V n and W n be subspaces of C n spanned by [ θ · n ] vectors in { v i } and { w j } respectively. We study the angle between V n and W n as n goes to infinity. We show that when { v i } and { w j } arise in certain arithmetically defined families, the angles between V n and W n may either tend to 0 or be bounded away from zero, depending on the behavior of an associated eigenvalue problem.

How to cite

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Brooks, Robert. "On the angles between certain arithmetically defined subspaces of ${\bf C}^n$." Annales de l'institut Fourier 37.1 (1987): 175-185. <http://eudml.org/doc/74742>.

@article{Brooks1987,
abstract = {If $\lbrace v_i\rbrace $ and $\lbrace w_j\rbrace $ are two families of unitary bases for $\{\bf C\}^n$, and $\theta $ is a fixed number, let $V^n$ and $W^n$ be subspaces of $\{\bf C\}^n$ spanned by $[\theta \cdot n]$ vectors in $\lbrace v_i\rbrace $ and $\lbrace w_j\rbrace $ respectively. We study the angle between $V^n$ and $W^n$ as $n$ goes to infinity. We show that when $\lbrace v_i\rbrace $ and $\lbrace w_j\rbrace $ arise in certain arithmetically defined families, the angles between $V^n$ and $W^n$ may either tend to $0$ or be bounded away from zero, depending on the behavior of an associated eigenvalue problem.},
author = {Brooks, Robert},
journal = {Annales de l'institut Fourier},
keywords = {eigenvalue; angle between subspaces; lower bounds},
language = {eng},
number = {1},
pages = {175-185},
publisher = {Association des Annales de l'Institut Fourier},
title = {On the angles between certain arithmetically defined subspaces of $\{\bf C\}^n$},
url = {http://eudml.org/doc/74742},
volume = {37},
year = {1987},
}

TY - JOUR
AU - Brooks, Robert
TI - On the angles between certain arithmetically defined subspaces of ${\bf C}^n$
JO - Annales de l'institut Fourier
PY - 1987
PB - Association des Annales de l'Institut Fourier
VL - 37
IS - 1
SP - 175
EP - 185
AB - If $\lbrace v_i\rbrace $ and $\lbrace w_j\rbrace $ are two families of unitary bases for ${\bf C}^n$, and $\theta $ is a fixed number, let $V^n$ and $W^n$ be subspaces of ${\bf C}^n$ spanned by $[\theta \cdot n]$ vectors in $\lbrace v_i\rbrace $ and $\lbrace w_j\rbrace $ respectively. We study the angle between $V^n$ and $W^n$ as $n$ goes to infinity. We show that when $\lbrace v_i\rbrace $ and $\lbrace w_j\rbrace $ arise in certain arithmetically defined families, the angles between $V^n$ and $W^n$ may either tend to $0$ or be bounded away from zero, depending on the behavior of an associated eigenvalue problem.
LA - eng
KW - eigenvalue; angle between subspaces; lower bounds
UR - http://eudml.org/doc/74742
ER -

References

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  1. [1] R. BROOKS, The Bottom of the Spectrum of a Riemannian Covering, Crelles J., 357 (1985), 101-114. Zbl0553.53027MR86h:58138
  2. [2] R. BROOKS, The Spectral Geometry of the Apollonian Packing, Comm. P. Appl. Math., XXXVIII (1985), 357-366. Zbl0575.52009
  3. [3] R. BROOKS, The Spectral Geometry of a Tower of Coverings, J. Diff. Geom., 23 (1986), 97-107. Zbl0576.58033MR87j:58095
  4. [4] GELFAND, GRAEV and PYATETSKII-SHAPIRO, Representation Theory and Automorphic Functions, W.B. Saunders Co., 1969. Zbl0177.18003MR38 #2093
  5. [5] H. HELSON and D. SARASON, Past and Future, Math. Scand., 21 (1967), 5-16. Zbl0241.60029MR38 #5282
  6. [6] A. SELBERG, On the Estimation of Fourier Coefficients of Modular Forms, Proc. Symp. Pure Math, VIII (1965), 1-15. Zbl0142.33903MR32 #93
  7. [7] A. WEIL, On Some Exponential Sums, Proc. Nat. Acad. Sci. USA, 34 (1948), 204-207. Zbl0032.26102MR10,234e

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