RT journal article T1 Well-posedness of time-fractional systems in vector-valued Hölder spaces A1 Alvarez, Edgardo A1 Lizama, Carlos A1 Murillo Arcila, Marina A2 Matemáticas K1 Well-posedness K1 block operator matrix K1 systems of nonlocal partial differential equations K1 vector-valued H¨older spaces K1 tempered fractional derivatives AB We fully characterize the well-posedness in vector-valued Hölder in time spaces of a nonlocalequation 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-valueda priori maximal Hölder inequalities. Our result also contains a characterization in the case of a singleclosed linear operator (not necessarily bounded), which is also new. We show that the condition that A isthe generator of an analytic semigroup is sufficient for the well-posedness. In particular, we show that thewell-posedness holds if the operators on the diagonal of A are generators of analytic semigroups and if theoff-diagonal entries satisfy a smallness condition. We exemplify our main results with abstract as well asconcrete models arising in fluid dynamics. PB Springer Nature SN 1424-3199 YR 2026 FD 2026-03 LK http://hdl.handle.net/10498/38911 UL http://hdl.handle.net/10498/38911 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 21-sep-2026