Today, however, the variable target function method has been superseded largely by the more efficient torsion angle dynamics algorithm.
Each restraint restricts the torsion angle to one allowed interval.
A countable torsion free group is free if and only if every subgroup of finite rank is free.
This seems to be inaccessible for general finitely-generated, torsion-free, nilpotent groups.
The same can be said of maps that can be analytically conjugated to hyperbolic torsions.
The other assertions of the proposition follow formally as in the torsion-free case.
Special emphasis is given to molecular dynamics in torsion angle space, the currently most efficient method for biomolecular structure calculation.
Since both algorithms work in torsion angle space, they have many features in common.
