My Ph.D. thesis supervised by ** J. Zimányi **
was written in 1981 [2] .
It describes a computer simulation of coupled hadronic
processes, in particular strange meson and hyperon
production in the framework of hadrochemistry
developed earlier by
** J. Zimányi ** and ** I. Montvay ** .
The entropy produced due to the approach
to chemical equilibrium between the different hadrons
is calculated locally in a relativistic hydrodynamical
description.

The description of finite volume effects in nucleon - deuteron mixtures
are based on an idea of ** B. Lukács **
[9,
11] .
The effect of a fast expansion of the nuclear fireball
on the deuteron - nucleon ratio, when the approach to
the chemical equilibrium is slower then its instantaneous
shift due to the expansion, is described in the
general classifying framework of Asymptotic Hadrochemistry
[15] .

In the first part of my long stay at the
University of Giessen
(1985 - 1994) I contributed to calculations of
photon and meson production in intermediate
energy heavy ion collisions by determining relativistic
production rates in elementary nucleon - nucleon
processes in the framework of different phenomenological
hadronic field theories
[21,
24 ,
26 ,
33 ,
34] .
These rates has been used
in collaboration with ** W. Cassing, U. Mosel, K. Niita
A de Paoli ** and ** G. Wolf **
in extended computer simulations
which described the heavy ion collisions in the framework
of nuclear transport theory.
In particular I tutored diplom works in this field
(** M. Schäfer, T. Vetter, A. Engel **).

After my return to Budapest (1994) I took part in the development
of a new model together with ** J. Zimányi ** and
** P. Lévai. ** This model is devoted to the description
of the hadronization of a quark matter, which is probably formed
in heavy-ion experiments at CERN (ALCOR model,
[42] .
The starting point in this model a thermalized quark matter
without gluons and diquarks. These quarks, also via intermedier
creation of diquarks, will be distributed in all possible ways
between the two lowest lying mesonic baryonic states.

In the early versions of this model the elementary processes,
which produced the hadrons, were calculated in analogy to the nuclear pick-up
reaction. This way from a quark and an antiquark a single pion was
created and the total momentum was balanced by the medium.
Recently we are working in a collaboration with ** S. Klevansky **
and ** P. Rehberg ** from the MPI Heidelberg on the description
of the elementray processes in the framework of the Nambu-Jona-Lasinio
model. In this case the hadron formation is accompanied by additional
quark antiquark pair creations.