dichotomize             Create dummy columns from logicals or factors
                        in a data frame
dig                     Search for rules
dig_correlations        Search for conditional correlations
dig_implications        Search for implicative rules
format_condition        Format condition - convert a character vector
                        to character scalar
is_subset               Determine whether the first vector is a subset
                        of the second vector
which_antichain         Return indices of first elements of the list,
                        which are incomparable with preceding elements.
