Fix SafeLeftDivide for rank-0 module inputs

Singular.lift misbehaves when A has 0 rows or B has 0 columns,
returning matrices with wrong shapes. Add early returns:
- nrows(A)==0: system has 0 equations, trivial solution X = 0_{c×s}
- ncols(B)==0: RHS is empty, solution must also be empty X = 0_{c×0}
In both cases X = zero_matrix(R, ncols(A), ncols(B)).

Bump version to v0.1.11

Author: kamalsaleh

Project.toml

@@ -1,6 +1,6 @@
 name = "MatricesForHomalg"
 uuid = "29b9b1b6-efa6-450e-8188-a5a2c25df071"
-version = "0.1.10"
+version = "0.1.11"
 authors = ["Mohamed Barakat <mohamed.barakat@uni-siegen.de>", "Johanna Knecht <johanna.knecht@student.uni-siegen.de>"]
 
 [deps]

ext/MatricesForHomalgSingularExt.jl

@@ -1047,6 +1047,14 @@ julia> SafeLeftDivide(A, B)
 ```
 """
 function MatricesForHomalg.SafeLeftDivide(A::Singular.smatrix, B::Singular.smatrix)
+    R = Singular.base_ring(A)
+    # Singular.lift misbehaves for rank-0 modules (0-row A or 0-column B).
+    # If A has 0 rows: system A*X=B has 0 equations → trivial solution X=0
+    # If B has 0 cols: system A*X=B with B empty → solution X must also be empty
+    # In both cases X has shape ncols(A) × ncols(B).
+    if Singular.nrows(A) == 0 || Singular.ncols(B) == 0
+        return Singular.zero_matrix(R, Singular.ncols(A), Singular.ncols(B))
+    end
     M_A = Singular.Module(A)
     M_B = Singular.Module(B)
     T, rest = Singular.lift(M_A, M_B)