I use "
0<F<1" in Latex, however in the pdf it is "
0 < F < 1 ", I want to reduce the space between text and <, just like "
0<F<1", would someone tell me how to do it?
That's because it's the intended spacing for binary relations. However, by simple braces you can change that, so that they would be treated like ordinary math characters:
An alternative in math mode is to use negative spaces defined by
\!. Each one will backshift characters by 1/6 quad.