Let f be a quadratic polynomial which has an irrationally indifferent fixed
point α. Let z be a biaccessible point in the Julia set of f. Then:
- In the Siegel case, the orbit of z must eventually hit the critical
point of f.
- In the Cremer case, the orbit of z must eventually hit the fixed point
α. Siegel polynomials with biaccessible critical point certainly exist,
but in the Cremer case it is possible that biaccessible points can never exist.
As a corollary, we conclude that the set of biaccessible points in the Julia
set of a Siegel or Cremer quadratic polynomial has Brolin measure zero.