Results 41 to 50 of about 179 (111)

The resolution of the Nirenberg-Treves conjecture [Elektronisk resurs]

open access: yes, 2006
We give a proof of the Nirenberg-Treves conjecture: that local solvability of principal-type pseudo-differential operators is equivalent to condition (Psi).
Dencker, Nils,, Lund University.
core  

Analytic hypoellipticity for sums of squares of vector fields

open access: yes, 1998
We discuss the open problem of analytic hypoellipticity for sums of squares of vector fields, including some recent partial results and a conjecture of ...
Himonas, A.
core  

Single-Trial MEG Data Can Be Denoised Through Cross-Subject Predictive Modeling. [PDF]

open access: yesFront Comput Neurosci, 2021
Ravishankar S, Toneva M, Wehbe L.
europepmc   +1 more source

The solvability of differential equations

open access: yes, 2010
It was a great surprise when Hans Lewy in 1957 presented a non-vanishing complex vector field that is not locally solvable. Actually, the vector field is the tangential Cauchy-Riemann operator on the boundary of a strictly pseudoconvex domain.
Dencker, Nils
core  

The Borel map in locally integrable structures. [PDF]

open access: yesMath Ann, 2020
Della Sala G, Cordaro PD, Lamel B.
europepmc   +1 more source

Optimal Gevrey regularity for certain sums of squares in two variables

open access: yes
For $ q $, $ a $ integers such that $ a \geq 1 $, $ 1 < q $, $ (x, y) \in U $, $ U $ a neighborhood of the origin in $ \R^{2} $, we consider the operator % $$ D_{x}^{2} + x^{2(q-1)} D_{y}^{2} + y^{2a} D_{y}^{2} .
Bove, Antonio, Mughetti, Marco
core   +1 more source

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