There exists a standard model of two Lagrangian submanifolds intersecting transversely at a point. Therefore, it suffices to construct a Lagrangian surgery neck for the standard intersection neighborhood \(X=\CC^n\), \(L_1=\RR^n\) and \(L_2=\jmath\RR^n\).
We start by picking a surgery profile curve,
\begin{align*}
\gamma: [-R, R] \to& \CC\\
t\mapsto& (a(t)+\jmath b(t))
\end{align*}
with the property that \(a(t), b(t)\) are non-decreasing, and there exists a value \(t_0\) so that
\(\gamma(t)=t\) for \(t< t_0\), and
\(\gamma(t)=\jmath t\) for \(t>t_0\).
We denote the are bounded between the real axis, imaginary axis, and curve \(\gamma\) by \(\lambda\).
An example is drawn in figure 0.0.1.
figure 0.0.1:Surgery Profile for Polterovich surgeryThis data provides a construction for the Lagrangian surgery neck:
\[
L_1\#_\gamma L_2:=\left\{(\gamma(t)\cdot x_1,\ldots, \gamma(t)\cdot x_n) \text{ such that } x_i \in \RR^n,t\in \RR, \sum_{i} x_i^2=1\right\}.
\]
Note that when \(t < t_0\) this parameterizes \((\RR\setminus B_r(0))\subset \CC^n\), and when \(t > t_0\) the chart parameterizes \((\jmath \RR \setminus B_r(0))\subset \CC^n\).
Therefore, this construction satisfies the condition that the surgery Lagrangian agrees with the surgery components outside of a small neighborhood of the surgery point.
This Lagrangian has the topology of \(S^{n-1}\times \RR\), which is the local model for the connect sum \(\RR^n\#_0\RR^n\).
Then (Polterovich surgery of Lagrangian submanifolds) follows by taking \(L_1\#_\gamma L_2\) for any suitable choice of \(\gamma\).