How has ragtime music influenced jazz music?

Ragtime is an important precursor to jazz but Iis not jazz. Ragtime is no more important than blues, gospel or folk music (American, European and African) in the development of jazz.

Check the Grove Dictionary of Jazz for a concise analysis of how ragtime contributed to jazz. That's always the best first stop when doing research. Check their sources out too.

Probably the only influence was its use of syncopation. There is quite a difference between the two genres, but the rhythm stresses and variations in ragtime had some influence. An example of this would be the use of eighth-note triplets in a duple meter.