Nodal lines of eigenfunctions of the fixed membrane problem in general convex domains

1994 ◽  
Vol 69 (1) ◽  
pp. 142-154 ◽  
Author(s):  
Giovanni Alessandrini
1994 ◽  
Vol 06 (05a) ◽  
pp. 999-1009 ◽  
Author(s):  
MARK S. ASHBAUGH ◽  
RAFAEL D. BENGURIA

We investigate the region of the plane in which the point (λ2/λ1, λ3/λ1) can lie, where λ1, λ2, and λ3 are the first three eigenvalues of the Dirichlet Laplacian on an arbitrary bounded domain Ω ⊂ ℝ2. In particular, by making use of a technique introduced by de Vries we obtain the best bounds to date for the quantities λ3/λ1 and (λ2 + λ3)/λ1. These bounds are λ3/λ1 ≤ 3.90514+ and (λ2 + λ3)/λ1 ≤ 5.52485+ and give small improvements over previous bounds of Marcellini. Where Marcellini used a bound due to Brands in his argument we use a better version of this bound which we obtain by incorporating deVries' idea. The other bounds that yield the greatest information about the region where points (λ2/λ1, λ3/λ1) can (possibly) lie are those due to Marcellini, Hile and Protter, and us (of which there are several, with two of them being new with this paper).


1973 ◽  
Vol 3 (3) ◽  
pp. 295-306 ◽  
Author(s):  
L.E. Payne ◽  
I. Stakgold

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