%0 Journal Article %A Alvarez, Edgardo %A Lizama, Carlos %A Murillo Arcila, Marina %T Well-posedness of time-fractional systems in vector-valued Hölder spaces %D 2026 %@ 1424-3199 %U http://hdl.handle.net/10498/38911 %X We fully characterize the well-posedness in vector-valued Hölder in time spaces of a nonlocal equation involving a closed operatormatrixAwith diagonal domain, defined on a product of Banach spaces, solely in terms of the norm boundedness of a block-operator-valued symbol. We also give vector-valued a priori maximal Hölder inequalities. Our result also contains a characterization in the case of a single closed linear operator (not necessarily bounded), which is also new. We show that the condition that A is the generator of an analytic semigroup is sufficient for the well-posedness. In particular, we show that the well-posedness holds if the operators on the diagonal of A are generators of analytic semigroups and if the off-diagonal entries satisfy a smallness condition. We exemplify our main results with abstract as well as concrete models arising in fluid dynamics. %K Well-posedness %K block operator matrix %K systems of nonlocal partial differential equations %K vector-valued H¨older spaces %K tempered fractional derivatives %~ Universidad de Cádiz