  The consequences of some symmetries of the three-alpha system are discussed.
In particular, the recent description of the low-energy spectrum of the 12C
nucleus in terms of the Algebraic Cluster Model (ACM) is compared to that of
the Semimicroscopic Algebraic Cluster Model (SACM). The previous one applies
interactions of a D3h geometric symmetry [1], while the latter one has a U(3)
multichannel dynamical symmetry, that connects the shell and cluster pictures.
The available data is in line with both descriptions.
