In this paper we study in detail, both analytically and numerically, the
dynamical properties of the triangle map, a piecewise parabolic automorphism of
the two-dimensional torus, for different values of the two independent
parameters defining the map. The dynamics is studied numerically by means of
two different symbolic encoding schemes, both relying on the fact that it maps
polygons to polygons: in the first scheme we consider dynamically generated
partitions made out of suitable sets of disjoint polygons, in the second we
consider the standard binary partition of the torus induced by the
discontinuity set. These encoding schemes are studied in detail and shown to be
compatible, although not equivalent. The ergodic properties of the triangle map
are then investigated in terms of the Markov transition matrices associated to
the above schemes and furthermore compared to the spectral properties of the
Koopman operator in L2(T2). Finally, a stochastic version of the triangle map
is introduced and studied. A simple heuristic analysis of the latter yields the
correct statistical and scaling behaviours of the correlation functions of the
original map.Comment: 45 pages, 30 figure