TITLE: A plausible hyperbolic link
QUESTION [9 upvotes]: This link is hyperbolic according to SnapPy's computation. There is an obvious non-boundary parallel annulus spanned by two components at the very top in the diagram. If this annulus is essential, then the link is not hyperbolic. Is this annulus inessential in the link exterior? If yes, how can one see it?

REPLY [8 votes]: As a complement (sorry) to Josh Howie's answer, here is my Snappy session.
In[1]: M = Manifold()
 Starting the link editor.
 Select Tools->Send to SnapPy to load the link complement.
 New triangulation received from PLink!
 In[2]: M.volume()
 Out[2]: 7.327724753
 In[3]: M.solution_type()
 Out[3]: 'contains degenerate tetrahedra'
Snappy is "guessing" that the manifold is not hyperbolic, but does have a hyperbolic piece in its JSJ decomposition.  (There is a lot of accuracy in the volume computation!) As Josh Howie points out, you can actually use Snappy (running under Sage) to prove that the manifold is not hyperbolic, and that that piece is a Borromean rings complement. (The .identify() method is your friend here.)

Added later: So I got snappy running under sage.  Here is that session.
sage: %gui tk
 sage: M = snappy.Manifold()
 Starting the link editor.
 Select Tools->Send to SnapPy to load the link complement.
 New triangulation received from PLink!
 sage: M.volume()
 7.32772475341777
 sage: M.solution_type()
 'contains degenerate tetrahedra'
 sage: M.splitting_surfaces()
 [Orientable two-sided with euler = 0]
 sage: M.split(0)
 [unnamed link.a(0,0)(0,0)(0,0), unnamed link.b(0,0)(0,0)(0,0)]
 sage: A, B = M.split(0)
 sage: A.identify()
 [t12067(0,0)(0,0)(0,0),
 6^3_2(0,0)(0,0)(0,0),
 L6a4(0,0)(0,0)(0,0),
 ooct02_00005(0,0)(0,0)(0,0)]
 sage: B.identify()
 [6^3_3(0,0)(0,0)(0,0)]
 sage: B.volume()
 -1.45994327738208e-14
 sage: A.volume()
 7.32772475341775
and we are done.  Snappy identified the two pieces (after splitting) as link complements.  Thus the splitting torus is incompressible. So the manifold A (which is the Borromean rings complement) is a geometric piece of the JSJ decomposition.  The other piece, a three-times punctured sphere crossed with the circle, is Seifert fibered and so is the other piece of the JSJ decomposition.