An example from the field of rigid body dynamics, possessing a natural
physical justification, is presented. The behaviour of the solutions
of the equations of motion in the real domain, whatever the initial da
ta, is regular; nevertheless, depending on the values of a certain con
trol parameter, the solution of the system may branch in the complex t
ime plane, and the system will have multi-valued first integrals. A de
numerable sequence of single-valued polynomial integrals of arbitraril
y high even degree is found (unlike Kovalevskaya's case, in which the
degree of the first integral of the Euler-Poisson equations is four).
As an extension, a system from non-holonomic mechanics is considered.
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