  We derive the integral operator form for the general rational solution of the
Yang-Baxter equation with $s\ell(2|1)$ symmetry. Considering the defining
relations for the kernel of the R-operator as a system of second order
differential equations we observe remarkable reduction to a system of simple
first order equations. The obtained kernel of R-operator has a very simple
structure. To illustrate all this in the simplest situation we treat also the
$s\ell(2)$ case.
