Denote our measure space as ( X , M , μ ) {\displaystyle (X,{\mathcal {M}},\mu )} .
Define the set N = { x : f ( x ) ≠ lim n → ∞ f ( x ) } {\displaystyle N=\{x:f(x)\neq \lim _{n\to \infty }f(x)\}} .
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