# Lee-Yang circle theorem

what is Lee-Yang circle theorem and what is it used for ?? , i mean given a measure how can you know that is Ferromagnetic and hence all its zeros lie on a Circle ??

the Lee-Yang circle theorem proof is it only valid for the measure $\delta (x-1) + \delta (x+1)$

how can you proof the Circle theorem for any measure ?? if any measure is positive and EVEN does Lee-Yang circle theorem hold ??

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