In our actual calculations of the two-dimensional Ising model, we are however always limited to a finite lattice and \( \xi \) will be proportional with the size of the lattice at the critical point. Through finite size scaling relations it is possible to relate the behavior at finite lattices with the results for an infinitely large lattice. The critical temperature scales then as $$ \begin{equation} T_C(L)-T_C(L=\infty) \propto aL^{-1/\nu}, \tag{2} \end{equation} $$ with \( a \) a constant and \( \nu \) defined in Eq. (1).