On Elementary Methods in Positivity Theory
Séminaire lotharingien de combinatoire, Tome 05 (1981)
Cet article a éte moissonné depuis la source Séminaire Lotharingien de Combinatoire website
We raise conjectures concerning the positivity of the power series coefficients of multi-variate rational functions. We also give a short proof of a result of Askey and Gasper that (1-x-y-z+4xyz)-b has positive power series coefficients for b>=(\sqrt{17}-3)/2. We show how Ismail and Tanharkar's proof that
(1-(1-L)x-Ly-Lxz-(1-L)yz+xyz)-a (where 0<=L<=1)
has positive power series coefficients for a=1 implies Koornwinder's result that it does so for a>=1.
The paper has been finally published under the same title in SIAM J. Math. Anal. 14 (1983), 396-398.
@article{SLC_1981_05_a4,
author = {Joe Gillis and Bruce Reznick and Doron Zeilberger},
title = {On {Elementary} {Methods} in {Positivity} {Theory}},
journal = {S\'eminaire lotharingien de combinatoire},
year = {1981},
volume = {05},
url = {http://geodesic.mathdoc.fr/item/SLC_1981_05_a4/}
}
Joe Gillis; Bruce Reznick; Doron Zeilberger. On Elementary Methods in Positivity Theory. Séminaire lotharingien de combinatoire, Tome 05 (1981). http://geodesic.mathdoc.fr/item/SLC_1981_05_a4/