Do Cauchy horizon's exist?

Question

Do Cauchy horizon's exist?

Answer 1

No, not with an apostophe.

Answer 2

If your trying to act like a smart a$$, try spell check.

Answer 3

As a mathematical construct within General Relativity (GR) they can indeed exist.

With a "normal" gravitational singularity (on rotating, no electric or other charge), the singularity itself is also the Cauchy horizon, but you probably mean one that has a finite size around the singularity.  Again, mathematically it is possible, but without visiting a real black hole we can't really know.

White holes and worm holes are also mathematical predictions of GR.  We haven't seen any of them so, GR mathematics alone does not necessarily demonstrate existence in the physical universe.

I suspect singularities are prevented from existing at all within a black hole due to quantum mechanical effects, though without the existance workable quantum gravity theory, this is only a hunch.