A note on the $M^*$--limiting convolution body

英文摘要：

We introduce the mixed convolution bodies of two convex symmetric bodies. We prove that if the boundary of a body $K$ is smooth enough then as $δ$ tends to $1$ the $δ$--$M^*$--convolution body of $K$ with itself tends to a multiple of the Euclidean ball after proper normalization. On the other hand we show that the $δ$--$M^*$--convolution body of the $n$--dimensional cube is homothetic to the unit ball of $\ell_1^n$.