Some languages treat certain digraphs as single letters for the purpose of collation. In general, where one such is formed as a ligature , the corresponding uppercase form is used in capitalization; where it is written as two separate characters, only the first will be capitalized. Thus Oedipus or Œdipus are both correct, but OEdipus is not. Examples with ligature include Ærøskøbing in Danish , where Æ/æ is a completely separate letter rather than merely a typographic ligature (the same applies in Icelandic); examples with separate characters are Llanelli in Welsh , where Ll is a single letter; and Ffrangeg in Welsh where Ff is equivalent to English F (whereas Welsh F corresponds to English V ).  Presentation forms, however, can use doubled capitals, such as the logo of the National Library of Wales ( Llyfrgell Genedlaethol Cymru ). The position in Hungarian is similar to the latter.