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Appendix A: Coefficients in the equations
The coefficients that appear in Eq. (31) can be computed with the help of a symbolic computation program. These
coefficients turn out to be rather cumbersome quotients of polynomic expressions in our
model with uniform twist, 
(A.1)
(A.2)
(A.3)
(A.4)Next,
we can compute the coefficients in Eq. (33), 
(A.5)
(A.6)Then,
the coefficients that appear in the boundary conditions (Eq. (56)) are given by
(A.7)
(A.8)The
coefficients that appear in the thin tube limit for the differential equations
(Eqs. (57), (58)) can be cast as 
(A.9)
(A.10)
The coefficients for the boundary conditions suitable for analytical solution
(Eq. 65), which also appear in the
dispersion relation (Eq. 66), are
(A.11)
(A.12)Finally,
the coefficients that appear on the sixth-order algebraic equation (Eq. 69) for m > 0 are
© ESO, 2011