  The pseudopotentials describing interaction of Laughlin quasielectrons (QE)
and quasiholes (QH) in an infinite fractional quantum Hall system are studied.
The QE and QH pseudopotentials are similar which suggests the (approximate)
particle--hole symmetry recovered in the thermodynamical limit. The problem of
the hypothetical symmetry-breaking QE hard-core repulsion is resolved by the
estimate that the ``forbidden'' QE pair state has too high energy and is
unstable. Strong oscillations of the QE and QH pseudopotentials persist in an
infinite system, and the analogous QE and QH pair states with small relative
angular momentum and nearly vanishing interaction energy are predicted.
