# The Exact renormalization group and approximate solutions

@article{Morris1994TheER, title={The Exact renormalization group and approximate solutions}, author={T. Morris}, journal={International Journal of Modern Physics A}, year={1994}, volume={9}, pages={2411-2450} }

We investigate the structure of Polchinski’s formulation of the flow equations for the continuum Wilson effective action. Reinterpretations in terms of I.R. cutoff Green’s functions are given. A promising nonperturbative approximation scheme is derived by carefully taking the sharp cutoff limit and expanding in “irrelevancy” of operators. We illustrate with two simple models of four-dimensional λφ4 theory: the cactus approximation, and a model incorporating the first irrelevant correction to… Expand

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