by **
W. Sickel**

**Preprint series:**
98-31, Analysis

**The paper is published:**
Forum Math., 10 (3), 303-327, 1998.

**MSC:**- 46E35 Sobolev spaces and other spaces of ``smooth'' functions, embedding theorems, trace theorems
- 47H30 Particular nonlinear operators (superposition, Hammerstein, Nemytskiui, Uryson, hysteresis operators, etc.), See also {45P05}

**Abstract:** Let $G : {Bbb R} \to {Bbb R}$ be a continuous function. Denote by $T_G$ the corresponding composition operator which sends $f$ to $G(f)$. Then we investigate consequences for the parameters $s, p,q$ and $r$ of the inclusion

\[ T_G \, (B^s_{p,q}({Bbb R})) \subset {B}^r_{p, \infty}({Bbb R}) . \]

Here $B^{s}_{p,q}$ denotes a Besov space.

**Keywords:** *composition operator, Nemytskij operator, Besov-Lizorkin-Triebel spaces*

**Upload:** 1999-02-10

**Update:** 1999-04-07

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