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On the two-dimensional Gierer-Meinhardt system with strong coupling. (English) Zbl 0955.35006

The authors study the Gierer-Meinhardt system \[ A_t= \varepsilon^2\Delta A- A+ A^p/H^q,\quad A> 0\quad\text{in }\Omega, \]
\[ \tau H_t= D\Delta H- H+ A^r/H^s,\quad H>0\quad\text{in }\Omega, \]
\[ {\partial A\over\partial\nu}= {\partial H\over\partial\nu}= 0\quad\text{on}\quad \partial\Omega. \] The unknowns \(A= A(x,t)\), \(H= H(x,t)\) represent the concentrations at a point \(x\in\Omega\) at time \(t\) of some biochemicals called activator and inhibitor, \(\varepsilon\), \(\tau\), \(D\) are positive constants and the exponents \(p\), \(q\), \(r\), \(s\) are assumed to satisfy the conditions \[ 1< p<\Biggl({N+ 2\over N-2}\Biggr)_+,\quad q> 0,\quad r>0,\quad s\geq 0,\quad 0<{p- 1\over q}<{r\over s+1}, \] where \(((N+ 2)/(N- 2))_+\) is \((N+ 2)/(N- 2)\) if \(N\geq 3\) and is \(+\infty\) if \(N= 1\) or 2. Using the Lyapunov-Schmidt reduction method, the authors study the associated stationary system for \(\varepsilon\to 0\) in the two-dimensional case, constructing solutions with isolated condensation points.

MSC:

35B25 Singular perturbations in context of PDEs
92C40 Biochemistry, molecular biology
35B40 Asymptotic behavior of solutions to PDEs
35J55 Systems of elliptic equations, boundary value problems (MSC2000)
92C15 Developmental biology, pattern formation
35K50 Systems of parabolic equations, boundary value problems (MSC2000)
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