From the fact that the two-dimensional moment problem is not always solvable, we can deduce that there must be extreme ray generators of the cone of positive definite double sequences which are nor moment sequences. Such an argument does not lead to specific examples. In this paper it is shown how specific examples can be constructed if one is given an example of an N-extremal indeterminate measure in the one-dimensional moment problem (such examples exist in the literature). Konrad Schmüdgen had an example similar to ours.
@article{urn:eudml:doc:43026,
title = {Extreme positive definite double sequences which are not moment sequences.},
journal = {Collectanea Mathematica},
volume = {54},
year = {2003},
pages = {87-98},
zbl = {1029.43002},
mrnumber = {MR1962946},
language = {en},
url = {http://dml.mathdoc.fr/item/urn:eudml:doc:43026}
}
Bisgaard, Torben Maack. Extreme positive definite double sequences which are not moment sequences.. Collectanea Mathematica, Tome 54 (2003) pp. 87-98. http://gdmltest.u-ga.fr/item/urn:eudml:doc:43026/