I've been pushing the limits of determinant calculation over
multivariate polynomial rings.  I can calculate determinants of
matrices up to 9x9 of the form [[x_0_0, x_0_1],[x_1_0, x_1_1]] (each
element is a single unique variable).  When I get to 10x10 is runs for
a while the crashes with:
Unhandled SIGSEGV: A segmentation fault occured in SAGE.
This probably occured because a *compiled* component
of SAGE has a bug in it (typically accessing invalid memory)
or is not properly wrapped with _sig_on, _sig_off.
You might want to run SAGE under gdb with 'sage -gdb' to debug this.
SAGE will now terminate (sorry).

  9x9 matrices only take about 40 seconds.  The 10x10 calculation runs
for a long time (>1 hr) before crashing.  This is on 64 bit Ubuntu
with the patch in Trac #4068 (http://trac.sagemath.org/sage_trac/
ticket/4068) applied.
  BTW, what is the underlying algorithm used for the determinants? As
I understand it, the naive way is O(N!) while the recursive way is
O(N^3) for a NxN matrix.
  Also, "occured" is misspelled in the error message.  It should be
"occurred".

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