Displaying similar documents to “A quasi-nilpotent operator with reflexive commutant, II”

Volume ratios in L p -spaces

Yehoram Gordon, Marius Junge (1999)

Studia Mathematica

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There exists an absolute constant c 0 such that for any n-dimensional Banach space E there exists a k-dimensional subspace F ⊂ E with k≤ n/2 such that i n f e l l i p s o i d ε B E ( v o l ( B E ) / v o l ( ε ) ) 1 / n c 0 i n f z o n o i d Z B F ( v o l ( B F ) / v o l ( Z ) ) 1 / k . The concept of volume ratio with respect to p -spaces is used to prove the following distance estimate for 2 q p < : s u p F p , d i m F = n i n f G L q , d i m G = n d ( F , G ) c p q n ( q / 2 ) ( 1 / q - 1 / p ) .

Universal solutions of a nonlinear heat equation on N

Thierry Cazenave, Flávio Dickstein, Fred B. Weissler (2003)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

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In this paper, we study the relationship between the long time behavior of a solution u ( t , x ) of the nonlinear heat equation u t - Δ u + | u | α u = 0 on N (where α &gt; 0 ) and the asymptotic behavior as | x | of its initial value u 0 . In particular, we show that if the sequence of dilations λ n 2 / α u 0 ( λ n · ) converges weakly to z ( · ) as λ n , then the rescaled solution t 1 / α u ( t , · t ) converges uniformly on N to 𝒰 ( 1 ) z along the subsequence t n = λ n 2 , where 𝒰 ( t ) is an appropriate flow. Moreover, we show there exists an initial value U 0 such that the set of all possible z attainable...