The fixed point property in direct sums and modulus R(a,X)
arXiv:1210.7823 · doi:10.1017/S0004972713000440
Abstract
We show that the direct sum of Banach spaces with a strictly monotone norm has the weak fixed point property for nonexpansive mappings whenever for each . In particular, enjoys the fixed point property if Banach spaces are uniformly nonsquare. This combined with the earlier results gives a definitive answer for r=2: the direct sum of uniformly nonsquare spaces with any monotone norm has FPP. Our results are extended for asymptotically nonexpansive mappings in the intermediate sense.
12 pages