Linearity and determinism seem to be two essential conditions for polynomial learning of grammars to be possible. We propose
a general condition valid for certain subclasses of the linear grammars given which these classes can be polynomially identified
in the limit from given data. This enables us to give new proofs of the identification of well known classes of grammars,
and to propose a new (and larger) class of linear grammars for which polynomial identification is thus possible.
Keywords Polynomial identification in the limit - linear grammars