I am looking into the amortized analysis of splay trees and seem to be missing something.
Pretty much every resource uses the accounting method which I believe I grasp. What confuses me is the part where an upper bound is put on credits:
$ δ≤3(r′(x)−r(x)) $ where $r'(x)$ is the rank of a node after splaying and $r(x)$ is the rank before.
Could someone help me with there the $3$ is coming from? It appears to be common knowledge which I'm missing as everyone just uses it as given. Thanks!