Univariate Polynomial Ring in x over Multivariate Polynomial Ring in y, z over Finite Field of size 7

R

F7[y,z][x]

Full MatrixSpace of 2 by 2 dense matrices over F7[y,z][x]

Error in lines 1-1
Traceback (most recent call last):
File "/cocalc/lib/python2.7/site-packages/smc_sagews/sage_server.py", line 1044, in execute
exec compile(block+'\n', '', 'single', flags=compile_flags) in namespace, locals
File "", line 1, in <module>
File "sage/structure/sage_object.pyx", line 173, in sage.structure.sage_object.SageObject.rename (build/cythonized/sage/structure/sage_object.c:2470)
raise NotImplementedError("object does not support renaming: %s" % self)
NotImplementedError: object does not support renaming: x

x