Meaning of Math Symbols in the Fundamental Theorem of Calculus

Question

I am learning the fundamental theorem of calculus, and in it I came across this symbol Š. My book does not explain what it means.

This is where I saw the symbol. What does this mean?

What does Š mean?

Answer 1

This symbol should be ≤ (or $\leq$ if the first one doesn't render): that is, "is less than or equal to". The typesetter for this book clearly hasn't done a very good job of it, and seems to have run into an encoding issue.

Answer 2

This is just a misprint or an encoding problem the actual notation is ' ≤ '.

Answer 3

I believe the author made a mistake and meant to write $\leq$.