No Arabic abstract
The treated matrix equation $(1+ae^{-frac{|X|}{b}})X=Y$ in this short note has its origin in a modelling approach to describe the nonlinear time-dependent mechanical behaviour of rubber. We classify the solvability of $(1+ae^{-frac{|X|}{b}})X=Y$ in general normed spaces $(E,|cdot|)$ w.r.t. the parameters $a,binmathbb{R}$, $b eq 0$, and give an algorithm to numerically compute its solutions in $E=mathbb{R}^{mtimes n}$, $m,ninmathbb{N}$, $m,ngeq 2$, equipped with the Frobenius norm.
Note that the family of closed curves C_N={(x,y)in R^2;x^(2N)+y^(2N)=1} for N=1,2,3,... approaches the boundary of [-1,1]^2 as N to infty. In this paper we exhibit a natural parameterization of these curves and generalize to a larger class of equations.
Let $f(x)=x^{2}(x^{2}-1)(x^{2}-2)(x^{2}-3).$ We prove that the Diophantine equation $ f(x)=2f(y)$ has no solutions in positive integers $x$ and $y$, except $(x, y)=(1, 1)$.
Suppose that $n$ is a positive integer. In this paper, we show that the exponential Diophantine equation $$(n-1)^{x}+(n+2)^{y}=n^{z}, ngeq 2, xyz eq 0$$ has only the positive integer solutions $(n,x,y,z)=(3,2,1,2), (3,1,2,3)$. The main tools on the proofs are Bakers theory and Bilu-Hanrot-Voutiers result on primitive divisors of Lucas numbers.
P/As-substitution effects on the transport properties of polycrystalline LaFeP$_{1-x}$As$_{x}$O$_{1-y}$F$_{y}$ with $x$ = 0 -- 1.0 and $y$ = 0 -- 0.1 have been studied. In the F-free samples ($y$ = 0), a new superconducting (SC) dome with a maximum $T_{c}$ of 12 K is observed around $x$ = 0 -- 0.3. This is separated from another SC dome with $T_{c}$ $sim$10 K at $x$ = 0.6 -- 0.8 by an antiferromagnetic region ($x$ = 0.3 -- 0.6), giving a two-dome feature in the $T_{c}-x$ phase diagram. As $y$ increases, the two SC domes merge together, changing to a double peak structure at $y$ = 0.05 and a single dome at $y$ = 0.1. This proves the presence of two different Fermi surface states in this system.
In this paper, we solve the equation of the title under the assumption that $gcd(x,d)=1$ and $ngeq 2$. This generalizes earlier work of the first author, Patel and Siksek [BPS16]. Our main tools include Frey-Hellegouarch curves and associated modular forms, and an assortment of Chabauty-type techniques for determining rational points on curves of small positive genus.