What does the rectangular symbol means in mathematica??

60 Views Asked by At

I was solving a problem related to inequality and there I get this root but I didn't get what does this rectangular symbol means ?

Image of the root and also symbol

The code for the mathematica is --

Reduce [10 p^3 (1 - p)^2 + 5 p^4 (1 - p) + p^3 < p, p]