In fact it was Pringsheim in 1898 who first noted that Lambert's proof was absolutely correct and exceptional for its time, since the expansion of the tangent function was not only written down formally, but also proved to be a convergent continued fraction.
Sa katunayan, ito ay Pringsheim sa 1898 na unang bantog na Lambert's patunay ay ganap na walang tama at katangi-tangi para sa kanyang oras, dahil sa ang pagpapalawak ng mga padaplis function ay hindi lamang nakasulat na down pormal, ngunit din proved na patuloy na nagtatagpo sa isang maliit na bahagi.