We discuss, on general grounds, how two subgraphs of a given Feynman graph can overlap with each other. For this, we use the notion connecting and returning lines that describe any subgraph is inserted within original graph. This, in turn, allows us to derive ``nonoverlap'' theorems for one-particle-irreducible 2, 3 4 external legs. As an application, provide simple justification skeleton expan...

there is a long tradition in economics about the question of whether intergenerational discounting is fair or not. ramsey (1928) was the first economist that criticized the discounting and mentioned that the just rate of discounting is zero.  in this paper it was tried to calculate the just rate of discounting for iran with respect to islamic thoughts. according to islam, intergenerational just...