Article Contents
Article Contents

Computation of the stochastic basin of attraction by rigorous construction of a Lyapunov function

The research for this paper was supported by the Icelandic Research Fund (Rannís) in the project `Lyapunov Methods and Stochastic Stability' (152429-051), which is gratefully acknowledged

• The γ-basin of attraction of the zero solution of a nonlinear stochastic differential equation can be determined through a pair of a local and a non-local Lyapunov function. In this paper, we construct a non-local Lyapunov function by solving a second-order PDE using meshless collocation. We provide a-posteriori error estimates which guarantee that the constructed function is indeed a non-local Lyapunov function. Combining this method with the computation of a local Lyapunov function for the linearisation around an equilibrium of the stochastic differential equation in question, a problem which is much more manageable than computing a Lyapunov function in a large area containing the equilibrium, we provide a rigorous estimate of the stochastic γ-basin of attraction of the equilibrium.

Mathematics Subject Classification: Primary: 37B25, 65P40, 93E03, 93E15, 93D30; Secondary: 60H35, 65C30.

 Citation:

• Figure 1.  Above: the computed non-local Lyapunov function $v$ for system (5.1). Below: the function $Lv$, approximating $-10^{-3}$

Figure 2.  Non-local Lyapunov function for system (5.2) with $\theta = 1$. The non-local Lyapunov functions looks very similar to the one computed in [3]

Table 1.  The table shows the Wendland function $\psi_0(r): = \phi_{8, 6}(cr)$ as well as the related functions $\psi_1$ to $\psi_6$, defined recursively by $\psi_{k+1}(r): = \frac{\partial_r \psi_k(r)}{r}$ for $k = 0, 1, \ldots, 5$

 $\phi_{8, 6}$ $\psi_0(r)$ $[46,189(cr)^6+73,206 (cr)^5+54,915(cr)^4+24,500(cr)^3$ $+6,755(cr)^2+1,078cr+77]\, (1- cr)^{14}_+$ $\psi_1(r)$ $-380\, c^2\, [2,431(cr)^5+2,931(cr)^4+1,638(cr)^3+518(cr)^2$ $+91cr+7]\, (1- cr)^{13}_+$ $\psi_2(r)$ $12,920\, c^4\, [1,287(cr)^4+1,108(cr)^3+426(cr)^2$ $+84cr+7]\, (1- cr)^{12}_+$ $\psi_3(r)$ $-620,160\, c^6\, [429 (cr)^3+239 (cr)^2+55 cr+5]\, (1- cr)^{11}_+$ $\psi_4(r)$ $112,869,120\, c^8\, [33(cr)^2+10cr+1]\, (1- cr)_+^{10}$ $\psi_5(r)$ $-4,966,241,280\, c^{10}\, [9cr+1]\, (1- cr)_+^{9}$ $\psi_6(r)$ $446,961,715,200\, c^{12}\, (1- cr)_+^{8}$

Table 2.  The table shows the Wendland function $\psi_0(r): = \phi_{7, 6}(cr)$ as well as the related functions $\psi_1$ to $\psi_6$, defined recursively by $\psi_{k+1}(r): = \frac{\partial_r \psi_k(r)}{r}$ for $k = 0, 1, \ldots, 5$

 $\phi_{7, 6}$ $\psi_0(r)$ $[4,096(cr)^6+7,059 (cr)^5+5,751(cr)^4+2,782(cr)^3+830(cr)^2$ $+143cr+11]\, (1- cr)^{13}_+$ $\psi_1(r)$ $-38\, c^2\, [2,048(cr)^5+2,697(cr)^4+1,644(cr)^3+566(cr)^2$ $+108cr+9]\, (1- cr)^{12}_+$ $\psi_2(r)$ $10,336\, c^4\, [128(cr)^4+121(cr)^3+51(cr)^2+11cr+1]\, (1- cr)^{11}_+$ $\psi_3(r)$ $-62,016\, c^6\, [320 (cr)^3+197 (cr)^2+50 cr+5]\, (1- cr)^{10}_+$ $\psi_4(r)$ $3,224,832\, c^8\, [80(cr)^2+27cr+3]\, (1- cr)_+^{9}$ $\psi_5(r)$ $-354,731,520\, c^{10}\, [8cr+1]\, (1- cr)_+^{8}$ $\psi_6(r)$ $25,540,669,440\,c^{12}\,(1- cr)_+^{7}$

Table 3.  The table shows values for $\psi_{k, i}: = \sup_{r\in[0, \infty)} |\psi_i(r)| r^k$ for the Wendland functions $\psi_0(r): = \phi_{8, 6}(cr)$ and $\psi_0(r): = \phi_{7, 6}(cr)$

 $\psi_{k, i}$ $\phi_{8, 6}$ $\phi_{7, 6}$ $\psi_{6, 6}$ $3.148511062 \cdot 10^7\cdot c^6$ $3.240130299 \cdot 10^6\cdot c^6$ $\psi_{5, 5}$ $2.363249538\cdot 10^6\cdot c^5$ $2.588617377\cdot 10^5\cdot c^5$ $\psi_{5, 4}$ $6.409097287\cdot 10^6\cdot c^6$ $6.534280933\cdot 10^5\cdot c^6$ $\psi_{4, 4}$ $1.947997580\cdot 10^5\cdot c^4$ $2.262550039\cdot 10^4\cdot c^4$ $\psi_{4, 3}$ $6.000016519\cdot 10^5 \cdot c^5$ $6.515237949\cdot 10^4 \cdot c^5$ $\psi_{4, 2}$ $2.215560450\cdot 10^6\cdot c^6$ $2.237953342\cdot 10^5\cdot c^6$ $\psi_{3, 3}$ $1.807542870\cdot 10^4\cdot c^3$ $2.219149087\cdot 10^3\cdot c^3$ $\psi_{3, 2}$ $6.618581621\cdot 10^4\cdot c^4$ $7.625999381\cdot 10^3\cdot c^4$ $\psi_{3, 1}$ $3.172360616 \cdot 10^5 \cdot c^5$ $3.414789975 \cdot 10^4 \cdot c^5$ $\psi_{3, 0}$ $3.1008\cdot 10^6\cdot c^6$ $3.1008\cdot 10^5\cdot c^6$ $\psi_{2, 2}$ $1.970990855\cdot 10^3\cdot c^2$ $2.550970282\cdot 10^2\cdot c^2$ $\psi_{2, 1}$ $9.418422390\cdot 10^3\cdot c^3$ $1.147899628\cdot 10^3\cdot c^3$ $\psi_{2, 0}$ $9.044\cdot 10^4\cdot c^4$ $1.0336\cdot 10^4\cdot c^4$ $\psi_{1, 1}$ $2.767275907\cdot 10^2\cdot c$ $3.766803387\cdot 10^1\cdot c$ $\psi_{1, 0}$ $2.66\cdot 10^3\cdot c^2$ $3.42\cdot 10^2\cdot c^2$
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