## Abstract

Let Ω be a region of

**R**^{ N },*N*≥ 2 with boundary ∂Ω. We say that ∂Ω is of class*C*^{1}if ∀*x*_{ 0 }∈ ∂Ω ∃*ε*> 0 such that within the ball*B*_{ ε }(*x*_{ 0 }) ≡ {|*x*−*x*_{ 0 }| <*ε*}, ∂Ω can be implicitly represented in a local system of coordinates as a level set of a function$$\Phi \in {C^1}\left( {{B_\varepsilon }\left( {{x_0}} \right)} \right),\quad {\text{such}}\,{\text{that}}\left| {\nabla \Phi } \right| \ne 0\quad {\forall _x} \in {B_\varepsilon }\left( {{x_0}} \right).$$

## Keywords

Minkowski Inequality Physical Assumption Newton Force Lagrangian Path Ideal Compressible Fluid
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## References

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