On Invariants of Second Order Linear Partial Differential Equations in Two Variables

摘要: In this paper we deal with second order linear partial differential equations (d.e.) over an abstract field (F,∂ 1, ∂ 2) of characteristic zero, define analogue transformations ”indeterminates” (special 1 and for such a field, consider equivalence d.e. relative to these 2 multiplications the unknown element by any F*. This will be reduced more simple one (Theorem 1), corresponding invariant rational functions described separation of“common type orbits” invariants shown 3). An analogical result was presented in [3].