Decision trees, DMX and CONTAINS (T-SQL)

I would appreciate answers to the following doubts I have regarding Decision trees, CONTAINS and using CONTAINS in a DMX query:

1. Does MS decision tree work only off equality/inequality conditions for the nodes? Is it possible to use a predicate as the branch criteria for a node?

2. Can the T-SQL predicate CONTAINS(...) be used in a DMX query? I need to check if a column-value is a substring of another column and create an intermediate column that will enable me to construct a decision tree with the phrase-present/absent branch.

3. Can CONTAINS(...) be used in a select clause? Like -

SELECT CONTAINS(JAT.column1, '"Good day"')

FROM JustAnotherTable;

4. Does CONTAINS(...) support both arguments to be column references? Or, is it mandatory that the pattern (argument #2) has to be a literal string or a variable? E.g.: I need to know the validity of the following expression -

SELECT * FROM JustAnotherTable JAT

WHERE CONTAINS(JAT.column1, JAT.column3);

The decision tree split conditions are based on equality/inequality conditions for categorical attributes and numeric/range comparisons for continuous values - we don't do arbitrary predicates.

CONTAINS is not supported in DMX.