# How to write “conditional one” in Latex [duplicate]

I want to write a "conditional one" in Latex but I don't know the precise name. It is a one with a double vertical dash that is equal to 1 if a condition is satisfied and 0 otherwise (a kind of Kronecker delta).

Could someone tell what is the name of this symbol and how to write it in Latex ?

• Have you tried `\mathbb{1}` (with appropriate fonts loaded)? – TeXnician Dec 19 '18 at 11:00
• Isn't the just the indicator function? Often just written as a bold 1 as many fonts are missing a double stroke 1. – daleif Dec 19 '18 at 11:00
• @TeXnician What do you mean by appropriate fonts ? – MysteryGuy Dec 19 '18 at 11:04
• @MysteryGuy not all fonts that provide double stroke letters provide it for all letters and numbers, some only for A-Z, some for A-Z + 1 etc. It all depends on the base setup you are using (of which you provided no information) – daleif Dec 19 '18 at 11:51