Hello, I get an error when I'm trying to use a const member function in a multi-index container, as a template parameter for indexed_by<>. This const member function comes from a base class, from which the class contained in the multiindex container is derived. The error is the following: /home/yardbird/documenti/work/prog/piranha/pyranha/Gsp/../../src/polynomial.h:41: error: could not convert template argument ‘&piranha::base_monomial_gmp_arraypiranha::double_cf::get_degree’ to ‘int (piranha::monomial_gmp_arraypiranha::double_cf::*)()const’ The member function is named "get_degree", and returns an integer. The base class is "base_monomial_gmp_array", the derived class is, unsurprisingly, "monomial_gmp_array". If I "lift" this function to the derived class, by re-defining it there, the problem disappears. I have a hunch that probably with some clever typedef or some static_cast wizardy this could be resolved, however my experiments have not resolved anything yet. Does anyone have an idea on how to proceed? Thanks in advance, Francesco Biscani.