  Large-scale comparisons between the poetry of Tang and Song dynasties shed
light on how words, collocations, and expressions were used and shared among
the poets. That some words were used only in the Tang poetry and some only in
the Song poetry could lead to interesting research in linguistics. That the
most frequent colors are different in the Tang and Song poetry provides a trace
of the changing social circumstances in the dynasties. Results of the current
work link to research topics of lexicography, semantics, and social
transitions. We discuss our findings and present our algorithms for efficient
comparisons among the poems, which are crucial for completing billion times of
comparisons within acceptable time.
