Derivative Embeddings in Vector-Valued Morrey Spaces

@misc{shahmurov2026derivative,
  title = {{Derivative Embeddings in Vector-Valued Morrey Spaces}},
  author = {Rishad Shahmurov and Veli Shahmurov},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.00292},
  eprint = {2610.00292},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.00292},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Derivative Embeddings in Vector-Valued Morrey Spaces
AU  - Rishad Shahmurov
AU  - Veli Shahmurov
PY  - 2026
DA  - 2026/10/07
PB  - arXiv
DO  - 10.48550/arxiv.2610.00292
UR  - https://arxiv.org/abs/2610.00292
AB  - We develop an intermediate-derivative theory for Banach-valued evolution classes with Morrey control in time. Let E_0↪ E be Banach spaces, m≥2, 1<p<∞, and 0≤λ<1. If u∈ℳ^p,λ(E_0) and u^(m)∈ℳ^p,λ(E), then every intermediate derivative satisfies u^(j)∈ℳ^p,λ((E_0,E)_j/m,∞), 0<j<m, with no UMD, Fourier type, or operator-valued multiplier assumption. The proof is based on an exact rational-frequency splitting of D^j, the Peetre K-functional, and the Hardy--Littlewood maximal operator on Morrey spaces. On the line the estimate has the scale-sharp multiplicative form. On finite intervals we construct a graph-Morrey extension and obtain the same embedding. The weak fine index is optimal for arbitrary Banach couples. Combining the derivative theorem with the exact Morrey trace theorem yields an exact onto trace formula for every u^(j), together with mixed Hölder/interpolation embeddings and a trace-powered p-to-q Morrey gain. If E_0hookc E, these embeddings become compact both in the same Morrey norm after an arbitrarily small loss of interpolation smoothness and in time-Hölder spaces above the derivative-trace threshold. For positive selfadjoint Hilbert scales we further improve the weak interpolation target to the fractional domain D(B^1−j/m) and show that this exponent is sharp.
ER  -