How to make "Real number symbol" (ℝ) in Mathematica

Question

How can I write the "Real number symbol" ℝ in Mathematica?

Answer 1

You can do it with escdsResc You could also replace R with any letters from a-z, both uppercase and lowercase, to get the double-struck version of the letter.

Another way is writing \[DoubleStruckCapitalR] or whatever character you want to be double-struck.

Reference: http://reference.wolfram.com/mathematica/guide/NotationalAlphabetCharacters.html#647579870

Answer 2

Be careful, escdsResc does not represent the domain of real numbers. For this purpose type escrealsesc or Reals.

In[1]:= TrueQ /@ {Element[Pi, \[DoubleStruckCapitalR]], Element[Pi, Reals]}
Out[1]= {False, True}