Unconditional applicability of Lehmer's measure to the two-term Machin-like formula for $\pi$

Sanjar M. Abrarov, Rehan Siddiqui, Rajinder K. Jagpal +1

Lehmer defined a measure $$\mu =\sum _{j=1}^J\frac{1}{{\log }_{10}\left(\left|{\beta }_j\right|\right)},$$ where the ${\beta }_j$ may be either integers or rational numbers in a Machin-like fo…