I have a problem understanding a definition at page 93 of 'from perturbative to constructive renormalization', that is related to Graph Theory, and he uses it on the proof of the uniform BPH theorem for [itex]\phi_4^4[/itex] ([itex]\lambda \phi^4[/itex] in [itex]D=4[/itex]).(adsbygoogle = window.adsbygoogle || []).push({});

You have a graphG, a forest of quadrupedsF, andga subgraph ofGcompatible with the tree structure ofF. [itex]B_F(g)[/itex] is defined as theancestor of. What meansginFUGancestorin this context?

Maybe this question doesn't belong here, I'm sorry if that's the case. I thought that it belonged here because it's related to renormalization.

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# I Question about a definition in Rivasseau's book

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