What is the Syntax error for ....is incomplete; more input is needed

Input: DSolve[-Sqrt[r] v h[t] - 2 r v Derivative[1][Xi[2]][t] == 0, h[t], t]
Output: {{h[t] → -2 Sqrt[r] Derivative[1][Xi[2]][t]}}

Input: LXi = {r*D[Xi[2][t], t] + Sqrt[r]*(-2 *Sqrt[r] * D[Xi[2][t], t])(*Xi[1][r,t]*), Xi[2][t]},
LPhi = {f[r, t] v + g[r, t]};
EDsI = SubstInfinitesimals[EDs, LXi, LPhi] 
Output: Syntax error:  ....is incomplete; more input is needed.

I’m expecting the Output to be a list of {0, 0, 0, 0, 0, 0, mathematical expression }. I cannot identify what is not there on input to complete the expression to compute the correct answer. This is the Mathematica package. Please advise further.

Unlikely that anyone can answer the question unless the definition for SubstInfinitesimals is provided.

Indeed SubstInfinitesimals was provided. That being said the previous input and output whereby its was a list of {0, 0, 0, 0, 0, mathematical expression, mathematical expression } were:

Input:  LXi = {r*D[Xi[2][t], t] + Sqrt[r] h[t], Xi[2][t]};
LPhi = {f[r, t] v + g[r, t]};
EDsI = SubstInfinitesimals[EDs, LXi, LPhi]

Output:   {0, 0, 0, 0, 0, -r g[r, t] - Sqrt[r] v h[t] - 2 r v Derivative[1][Xi[2]][t] + v \!\(\*SuperscriptBox[\(f\), 
TagBox[RowBox[{"(", RowBox[{"0", ",", "1"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] + 
\!\(\*SuperscriptBox[\(g\), TagBox[RowBox[{"(", RowBox[{"0", ",", "1"}], ")"}],Derivative],
MultilineFunction->None]\)[r, t] + v \[Rho] \!\(\*SuperscriptBox[\(f\), TagBox[RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] - v \[Alpha] \[Lambda][r, t] \!\(\*SuperscriptBox[\(f\), TagBox[RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],
MultilineFunction->None]\)[r, t] + r v \[Beta] \[Lambda][r, t] \!\(\*SuperscriptBox[\(f\), TagBox[
RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] + \[Rho] 
\!\(\*SuperscriptBox[\(g\), TagBox[RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],
MultilineFunction->None]\)[r, t] - \[Alpha] \[Lambda][r, t] \!\(\*SuperscriptBox[\(g\), TagBox[
RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] + r \[Beta] \[Lambda][r, t] \!\(\*SuperscriptBox[\(g\), TagBox[RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],
MultilineFunction->None]\)[r, t] + 1/2 r v \[Sigma]^2 \!\(\*SuperscriptBox[\(f\), TagBox[RowBox[{"(", 
RowBox[{"2", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] + 1/2 r \[Sigma]^2 
\!\(\*SuperscriptBox[\(g\), TagBox[RowBox[{"(", RowBox[{"2", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t], -((\[Rho] h[t])/(   2 Sqrt[r])) + (\[Sigma]^2 h[t])/(
  8 Sqrt[r]) + (\[Alpha] h[t] \[Lambda][r, t])/(2 Sqrt[r]) + 1/2 Sqrt[r] \[Beta] h[t] \[Lambda][r, t] - 
  Sqrt[r] Derivative[1][h][t] +   r \[Beta] \[Lambda][r, t] Derivative[1][Xi[2]][t] - 
  r (Xi[2]^\[Prime]\[Prime])[t] - \[Alpha] Xi[2][t] \!\(\*SuperscriptBox[\(\[Lambda]\),TagBox[RowBox[{"(", 
RowBox[{"0", ",", "1"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] + r \[Beta] Xi[2][t] 
\!\(\*SuperscriptBox[\(\[Lambda]\), TagBox[RowBox[{"(", RowBox[{"0", ",", "1"}], ")"}],Derivative],
MultilineFunction->None]\)[r, t] + r \[Sigma]^2 \!\(\*SuperscriptBox[\(f\), TagBox[RowBox[{"(", 
RowBox[{"1", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] - Sqrt[r] \[Alpha] h[t] 
\!\(\*SuperscriptBox[\(\[Lambda]\), TagBox[RowBox[{"(",RowBox[{"1", ",", "0"}], ")"}],Derivative],
MultilineFunction->None]\)[r, t] + r^(3/2) \[Beta] h[t] \!\(\*SuperscriptBox[\(\[Lambda]\), TagBox[
RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] - r \[Alpha] Derivative[1][Xi[2]][t] \!\(\*SuperscriptBox[\(\[Lambda]\), TagBox[RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}],Derivative],MultilineFunction->None]\)[r, t] + r^2 \[Beta] Derivative[1][Xi[2]][t] 
\!\(\*SuperscriptBox[\(\[Lambda]\), TagBox[RowBox[{"(",RowBox[{"1", ",", "0"}], ")"}],Derivative],
MultilineFunction->None]\)[r, t]}

Hope this is clearer.

I have attached a .nb file to show how evaluation of the inputs results in outputs, particularly for EDsI[[6]]. I am not sure what is incorrect from the syntax.

Practice1.nb (40.4 KB)

You still haven’t shown us the definitions for SubstInfinitesimals and EDs