This function adds category features to the IntArray meanings, removes any doubles
and sets initial values to scores and usage, and indicates to which constituent (group)
the categories belong.
This class implements the construction and maintanance of the context
Each element of the context is a geometrical figure that is specified by
certain features.
Returns the largest substring of two strings if the substring is either at the start or at the end of
both strings and if the substring is not equal to either of the two strings.
Constructs a meaning with the given feature vector as the new
prototype, an id, its cover and its hierarchical layer.
The cover also indicates on which dimensions the prototypes are added.
This function updates the frequency with which it has been able to encode or decode an expression,
irrespective of whether it was finally selected or not.