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2 votes
1 answer
133 views

Global first integral for certain $3$ dimensional system

A physicist colleague asks me the following question. I have no idea to answer him. Your answer is very appreciated. Is there a global first integral on $\mathbb{R}^3$ for the following vector field? ...
Ali Taghavi's user avatar
5 votes
1 answer
414 views

Fredholm index vs. Limit cycle theory

Let $A$ be the algebra of all smooth functions $f: \mathbb{R}^2 \to \mathbb{R}$ such that $f$ is flat at the origin and is real analytic on $\mathbb{R}^2 \setminus \{0\}$. Let $B $ be ...
Ali Taghavi's user avatar
-4 votes
1 answer
871 views

Existence and uniqueness of solutions for a system of first order PDEs [closed]

Which results can be applied and which conditions are needed, to ensure the existence and uniqueness of the solutions of the first order of PDEs: A$\dfrac{\partial}{\partial t}\pmb{v}(t,x)=B(t,x,\pmb{...
Fernando's user avatar
  • 103
3 votes
2 answers
361 views

Regularity of a nonlinear ODE [Traveling wave solutions of parabolic systems]

In the book of Volpert on Traveling wave solutions of Parabolic Systems (AMS), one reads "the following assertion is readily proved and we shall not discuss it in detail". The same result is tacitely ...
Kosh's user avatar
  • 364