What does the Grothendieck's period conjecture mean?

Question

I would like to know how is the Grothendieck's period conjecture about algebraic cycles, defined explicitly ? and, what link has it with the Hodge conjecture for smooth complexe algebraic projective variety ? Which kind of books available on the net, nead we to learn to become able to understand easily this conjecture ?

Thanks a lot for your help.

Answer 1

I'm currently not studying this subject in math, but I found some websites that may help.

http://user.math.uzh.ch/ayoub/PDF-Files/periods-GKZ.pdf

http://arxiv.org/pdf/1307.1045.pdf

https://mathoverflow.net/questions/99791/on-grothendiecks-period-relations

I hope I helped :)