... Finikov had derived differential equations that determine all principal on a given surface, and Byushgens had obtained differential equations that determine surfaces which have a given linear element and admit a bending on a principal base. However, the question of solubility of these equations, in general, remained unclear.
... Finikov had nagmula kaugalian equation na matukoy ang lahat ng punong-guro sa isang ibabaw, at Byushgens had makuha kaugalian equation na matukoy ibabaw na kung saan ay may isang binigay na sa guhit na sangkap at kumilala ng isang bending sa isang punong-guro base. Gayunman, ang mga tanong ng solubility ng mga equation, sa pangkalahatan, naiiwan ang hindi maliwanag.