Flie fails to return a solution

[ivan-gavran]

For the input below, one would expect to receive output F(green & rectangle). However, that does not happen.

{
"literals":["red", "green", "blue", "circle", "rectangle", "triangle"],
"negative":
  [
    "red,circle;blue, triangle | green, triangle; red, rectangle; blue,rectangle",
    "green, triangle; green, triangle | green, circle; green, triangle; green, circle",
    "green,circle; red, triangle | blue, circle; blue, triangle; blue, triangle"
  ],
"positive":
  [
    "green,rectangle; blue, triangle | green, triangle; red, rectangle; blue, rectangle",
"green, triangle; green, triangle | green, circle; green, triangle; green, rectangle",
"green,circle; red, triangle | green, rectangle; red, triangle; blue, rectangle"
  ],
"number-of-formulas": 2,
"max-depth-of-formula": 4,
"operators":["F", "->", "&", "|", "U", "G", "X"]
}

[ivan-gavran]

it seems that it is a depth issue, because if depth is set to 5, the formula F(green & rectangle) is found