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To simplify notation, let us note in this proof $\rho = 8$ and $\alpha = 4$. The property $B_r^\bullet(\bar{T}_n^{(p)}) = \Delta$ holds if and only if $\mathcal{T}_n^{(p)}$ is obtained from $\Delta$ by gluing to the top boundary³ an arbitrary triangulation with a semi-simple alternating boundary of length $2q$, and with $n-N$ black triangles, and if the distinguished vertex is chosen among the inner vertices of the glued triangulation. Thus:

P(Br(Tˉn(p))=Δ)=BnN,qBn,p#inner vertices in glued triangulation#inner vertices in total triangulation.(5.3) \mathbb{P} (B_r^\bullet (\bar{T}_n^{(p)}) = \Delta) = \frac{B_{n-N,q}}{B_{n,p}} \cdot \frac{\#\text{inner vertices in glued triangulation}}{\#\text{inner vertices in total triangulation}}. \quad (5.3)

Therefore:

limnP(Br(Tˉn(p))=Δ)=C(q)C(p)ρN.(5.4) \lim_{n \to \infty} \mathbb{P} (B_r^\bullet (\bar{T}_n^{(p)}) = \Delta) = \frac{C(q)}{C(p)} \rho^{-N}. \quad (5.4)

As we have:

N=M(Δ)p+vFN(Mv)=1iqτip+vFN(Mv)=q+vF(cv+N(Mv))p, N = |\mathcal{M}(\Delta)| - p + \sum_{v \in \mathcal{F}^*} N(M_v) = \sum_{1 \le i \le q} |\tau_i| - p + \sum_{v \in \mathcal{F}^*} N(M_v) = q + \sum_{v \in \mathcal{F}^*} (c_v + N(M_v)) - p,

we get:

limnP(Br(Tˉn(p))=Δ)=ρqC(q)ρpC(p)vFρcvρN(Mv). \lim_{n \to \infty} \mathbb{P} (B_r^\bullet (\bar{T}_n^{(p)}) = \Delta) = \frac{\rho^{-q} C(q)}{\rho^{-p} C(p)} \prod_{v \in \mathcal{F}^*} \rho^{-c_v} \rho^{-N(M_v)}.

Now, since $\sum_{v \in \mathcal{F}^*} (c_v - 1) = p - q$, we can multiply the right-hand side by $(\alpha\rho)^{p-q-\sum_{v \in \mathcal{F}^*} (c_v-1)}$, which yields:

limnP(Br(Tˉn(p))=Δ)=αqC(q)αpC(p)vFρ1αcv+1ρN(Mv), \lim_{n \to \infty} \mathbb{P} (B_r^\bullet (\bar{T}_n^{(p)}) = \Delta) = \frac{\alpha^{-q} C(q)}{\alpha^{-p} C(p)} \prod_{v \in \mathcal{F}^*} \rho^{-1} \alpha^{-c_v+1} \rho^{-N(M_v)},

that is:

limnP(Br(Tˉn(p))=Δ)=αqC(q)αpC(p)vFθ(cv)ρN(Mv)Z(cv+1), \lim_{n \to \infty} \mathbb{P} (B_r^\bullet (\bar{T}_n^{(p)}) = \Delta) = \frac{\alpha^{-q} C(q)}{\alpha^{-p} C(p)} \prod_{v \in \mathcal{F}^*} \theta(c_v) \frac{\rho^{-N(M_v)}}{Z(c_v + 1)},

for $\theta(k) = \rho^{-1}\alpha^{-k+1}Z(k+1)$. $\square$

Let us give a few properties of $\theta$ that will be useful in the sequel. These properties are obtained from the analytic combinatorial work in [9], rather than explicit enumeration as was the case for usual triangulations in [13].

First, the asymptotics of Z give:

θ(k)k123πk5/2.(5.5) \theta(k) \sim_k \frac{1}{2} \sqrt{\frac{3}{\pi}} k^{-5/2}. \quad (5.5)

Moreover, $\theta$ has the following generating function $g_\theta$:

gθ(x)=k=0θ(k)xk=13(4x1x+1)21x[0,1].(5.6) g_\theta(x) = \sum_{k=0}^{\infty} \theta(k)x^k = 1 - \frac{3}{\left(\sqrt{\frac{4-x}{1-x}} + 1\right)^2 - 1} \quad \forall x \in [0, 1]. \quad (5.6)

³Note that, as $\Delta$ is rooted, we can fix an arbitrary rule to determine where to glue the root of the other triangulation.