sentences:  Thus, for example, the code point U+FB00 (the typographic ligature "ﬀ") is defined to be compatible—but not canonically equivalent—to the sequence U+0066 U+0066 (two Latin "f" letters).Compatible sequences may be treated the same way in some applications (such as sorting and indexing), but not in others; and may be substituted for each other in some situations, but not in others.Sequences that are canonically equivalent are also compatible, but the opposite is not necessarily true.