pub fn common_space<FS: OrderedRingStructure + FieldStructure, SP: Borrow<AffineSpace<FS>> + Clone>(
space1: SP,
space2: SP,
) -> Option<SP>pub fn common_space<FS: OrderedRingStructure + FieldStructure, SP: Borrow<AffineSpace<FS>> + Clone>(
space1: SP,
space2: SP,
) -> Option<SP>