Degree functions for the leading term (wrt. the monomial ordering)
==================================================================

p_Deg: a degree that is compatible with the monomial ordering
       (i.e. for dp: totaldegree, for lp(lex): exponent of first variable(s), etc.)
p_FDeg: a degree for use in GB computations:
       (i.e. p_Deg for degree orderings, p_Totaldegree for block orderings (lex)
        or mixed orderings).
       Requirement: there are only finitely many monomials of the same degree
       Remark: A weight 0 (or positive and negative weights) allow infinitely
       many monomials of the same degree which lead to infinite cycles in GB
       computations - p_FDeg uses p_Totaldegree in this case
p_Totaldegree: the sum of all exponents (the usual total degree)
p_WTotaldegree: the weighted sum of all exponents(the usual weigthed degree)*OrdSgn
                For matrix orderings this is the scalar product of the first row
                of the ordering matrix with the exponent vector
p_WDegree: the weighted sum of all exponents (obsolete, currently not used):
           Difference to p_WTotaldegree:
           - does not muliply by OrdSgn
           - uses p_WFirstTotalDegree for the first block
           - for all but the first block: use the first non-zero entry in each
             column of the ordering matrix as weight (and not the entry in the
             first row)
p_WFirstTotalDegree: the weighted sum of the exponents of the first block
             (scalar product of the first row of the ordering matrix
             with the exponent vector)

Degree function for a polynomial
==================================
p_LDeg: return the length and the maximal degree wrt. p_FDeg

Ring properties wrt. monomial orderings
=======================================
OrdSgn: 1 for well orderings (i.e. 1 is the smallest monomial)
        -1 otherwise
MixedOrder: 0 for well orderings
         and local orderings (i.e. 1 is the largest monomial)
        1 otherwise
LexOrder: 1 for block orderings (incl. lex), 0 otherwise

