when I start version 4b5 with -O flag to get the compatibility mode, I
get the following:
Variable: 'AbsoluteIrreducibilityTest' must have a value
#I Now the destructive part of the GAP 3 compatibility mode
#I is loaded.
#I This makes certain GAP 4 facilities unusable.
#I (If I would be in favour of misusing the literature then
#I I would express the effect of loading this mode as follows.
#I ``Lasciate ogni speranza, voi ch' entrate!'')
Variable: 'Domain' is read only
not in any function
Entering break read-eval-print loop, you can 'quit;' to quit to outer loop,
or you can return after making it writable to continue