I think its this symbol
What mathematical symbol? Different symbols were invented in different times and places.
The symbol is *
"why" is not a mathematical symbol.
There is no standard symbol for subring
It's a mathematical metaphor.
The mathematical symbol for "undefined" is the infinity symbol.
The symbol is f, for frequency.
A. C. Leisenring has written: 'Mathematical logic and Hilbert's & symbol' -- subject(s): Symbolic and mathematical Logic 'Mathematical logic and Hilbert's E-Symbol'
The mathematical constant Pi has the symbol π
< this symbol can also mean less than