Why we get inequality form an equation? In the paper linear forms in the logarithms of real algebraic numbers close to 1, it is written on page 5 that-
$\varLambda \leq \frac{1}{by^n}$ (see equation 7 on page 5) 
But we get it from an equation. As I understand , it should be   $\varLambda = \frac{1}{by^n}$. 
How   $\varLambda$ could be less than $\frac{1}{by^n}$?
If it is  $\varLambda \leq \frac{1}{by^n}$ then why not  $\varLambda \geq \frac{1}{by^n}$?

From $$\tag6(b+1)x^n-by^n=1$$ we find after dividing by $by^n$
$$\left(1+\frac1b\right)\left(\frac xy\right)^n-1=\frac1{by^n}.$$
This certainly implies (as long as $b,y>0$) that also 
$$\left|\left(1+\frac1b\right)\left(\frac xy\right)^n-1\right|\le \frac1{by^n}.$$
