Search results for "Commutator"
showing 7 items of 37 documents
The Equationally-Defined Commutator
2015
On the Estimate for Commutators in DiPerna–Lions Theory
2011
In this note, we will exhibit the estimates on the commutator of semi-groups, motivated by commutator estimates in Di Perna-Lions theory.
On a problem of P. Hall for Engel words
2011
Commutators, C0-semigroups and resolvent estimates
2004
Abstract We study the existence and the continuity properties of the boundary values on the real axis of the resolvent of a self-adjoint operator H in the framework of the conjugate operator method initiated by Mourre. We allow the conjugate operator A to be the generator of a C 0 -semigroup (finer estimates require A to be maximal symmetric) and we consider situations where the first commutator [ H ,i A ] is not comparable to H . The applications include the spectral theory of zero mass quantum field models.
Off-diagonal estimates for bi-parameter commutators
2022
Tutkimme kahden parametrin singulaari-integraalien kommutaattoreiden rajoit-tuneisuutta iteroitujen avaruuksien[b, T]:Lp1Lp2→Lq1Lq2välillä kunqi, pi∈(1,∞)ja erityisesti fraktionaalisessa tilanteessaqi6=pi. Yhteensä seitsemässä ta-pauksessa yhdeksästä saavutamme täyden karaterisoinnin rajoittuneisuudella symboliabkoskevillaoskillatorisilla testiehdoilla. We study the boundedness of commutators of bi-parameter singular integrals between mixed spaces [b,T]:Lp1Lp2→Lq1Lq2 in the off-diagonal situation qi,pi∈(1,∞) where we allow qi≠pi. Boundedness is fully characterized in terms of oscillatory testing conditions on the function b for a total seven out of the nine possible arrangements of the inte…
The action of a compact Lie group on nilpotent Lie algebras of type {{n,2}}
2015
Abstract We classify finite-dimensional real nilpotent Lie algebras with 2-dimensional central commutator ideals admitting a Lie group of automorphisms isomorphic to SO 2 ( ℝ ) ${{\mathrm{SO}}_{2}(\mathbb{R})}$ . This is the first step to extend the class of nilpotent Lie algebras 𝔥 ${{\mathfrak{h}}}$ of type { n , 2 } ${\{n,2\}}$ to solvable Lie algebras in which 𝔥 ${{\mathfrak{h}}}$ has codimension one.
The Equationally-Defined Commutator in Quasivarieties Generated by Two-Element Algebras
2018
The notion of the equationally-defined commutator was introduced and thoroughly investigated in (Czelakowski, 2015). In this work the properties of the equationally-defined commutator in quasivarieties generated by two-element algebras are examined. It is proved: If a quasivariety Q is generated by a finite set of two-element algebras, then the equationally-defined commutator of Q is additive (Theorem 3.1) Moreover it satisfies the associativity law (Theorem 3.6). The second result is strengthened if the quasivariety is generated by a single two-element algebra 2: If Q = SP(2), then the equationally-defined commutator of Q universally validates one of the following laws: [x,y] = x^y or [x,y…