6,898 research outputs found
Embedding into Banach spaces with finite dimensional decompositions
This paper deals with the following types of problems: Assume a Banach space
has some property (P). Can it be embedded into some Banach space with a
finite dimensional decomposition having property (P), or more generally, having
a property related to (P)? Secondly, given a class of Banach spaces, does there
exist a Banach space in this class, or in a closely related one, which is
universal for this class?Comment: 26 page
Multispectral imaging of Mars from a lander
Multispectral imaging of Mars from lande
The tails in the Helix Nebula NGC 7293
We have examined a stream-source model for the production of the cometary
tails observed in the Helix Nebula NGC 7293 in which a transonic or moderately
supersonic stream of ionized gas overruns a source of ionized gas. Hydrodynamic
calculations reveal velocity structures which are in good agreement with the
observational data on tail velocities and are consistent with observations of
the nebular structure. The results also are indicative of a stellar atmosphere
origin for the cometary globules. Tail remnants persist for timescales long
enough for their identification with faint striations visible in the nebula gas
to be plausible.Comment: 7 pages, 6 figures, accepted for publication in A&
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