Did Kasparov and Fischer meet in secret and play with eachother?
fischer v kasparov may or may not have happened, but fischer did play online chess before he died. youtube search "fischer's secret games"
Considering how much Bobby hated the Russians and that Kasparov wasn't world champ until a decade after Fischer stopped playing, it's not likely Bobby played Kasparov "in secret." Bobby wasn't rich and a match with Kasparov would have brought money to both men.
I remember reading somewhere that Fischer met with Anand back in the early 90's at a European cafe and praised him for standing up to the Russian chess system. I cannot confirm the details or even if it's true but it sounds plausible.
According to this interview with Anand, it seems like he met Bobby Fischer only once, and that was in 2006.
https://www.theguardian.com/sport/2011/dec/02/vishy-anand-small-talk-interview
Garry Kasparov has written an article about his "encounter" with Bobby Fischer:
http://www.nybooks.com/articles/2011/03/10/bobby-fischer-defense/
But this could be a cover-up, denying the world the truth about encounters of the world's greatest masters.
a bad little kid moved into my neighborhood.
How is he bad?
Well, he put some tacks on the teacher´s chair
and puts chewing gum in little girl´s hair
I tried telling him:
Hey, junior, behave yourself but he just pointed me the middle finger.
Could you share with us the scientific paper that makes your statement true?
Yes, as title instructs - Did these two, masters of their games, meet in secrecy and play with eachother? There are no records of game between them, but that is only official. Do you think they attended unofficial business together?