User blog comment:Cello freak/Should the Kane chronicle's world and Percy Jackson's world exist side by side?/@comment-4485028-20110928022850

They do exist side by side according to what Amos said about different gods being in Manhattan, as well as when Carter comments on seeing a Pegasus.

What I would love is if for some reason Carter and Sadie had to take a train or something and one of them happened to sit next to or overhear a character from Heroes of Olympus series.