Name
orbl (surface) — Is a normal surface orientable?
Description
An orbl (surface) element stores whether or not a normal surface is
orientable.
Parents
The following elements contain orbl (in the
context of the orientability of a normal surface):
surface.
Children
Element orbl (in the context of the
orientability of a normal surface) has no children.
Attributes
value
Either T or F, according to
whether the parent surface is orientable or non-orientable respectively.
Past versions of Regina (versions 4.92 and earlier) used
true or 1 instead of
T, used
false or -1 instead of
F, and also used
unknown or 0 to indicate
that this property was unknown.
