I am trying to understand the classic 1998 PageRank paper (from the Google guys). I'm confused here:

"In matrix notation we have R' = c(AR' + E). Since ||R'||_1 = 1, we can rewrite this as R' = c(A + E x 1)R' where 1 is the vector consisting of all ones"

How did the paper go from "(AR' + E)" to "(A + E x 1)R'"? I don't understand.

R' is a vector of size n, A is an n x n matrix, and E is a vector of size n.