Meaning of this symbol

Question

What is the mathematical meaning of a horizontal A. I mean that it is like this > but crossed which makes it look like a horizontal A.

Answer 1

Usually, a slash on symbols in mathematics indicates a negation of the original meaning of the symbol.

For example, \begin{align}=\quad&\to\quad\ne\quad(\text{equality})\\\mid\quad&\to\quad\nmid\quad(\text{divisibility})\\\in\quad&\to\quad\notin\quad(\text{element})\\>\quad&\to\quad\ngtr\quad(\text{greater than})\\<\quad&\to\quad\not\lt\quad(\text{less than})\\\sim\quad&\to\quad\nsim\quad(\text{distribution})\end{align}

Answer 2

$\ngtr$ means not being superior (greater) than something. It is the negation of $>$

Answer 3

"≥" This means "equal or greater than"
">" This means "greater than" (being equal is not included)
"≯" This means "no greater than" <= What the hey is the difference between this brat and "≤"???