Each page in a PDF document is identified by an integer page index that expressesthe page’s relative position within the document. In addition, a document mayoptionally define page labels (PDF 1.3) to identify each page visually on the screenor in print. Page labels and page indices need not coincide: the indices are fixed,running consecutively through the document starting from 0 for the first page,but the labels can be specified in any way that is appropriate for the particulardocument.
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