# Up tack

The up tack or falsum (, `\bot` in LaTeX, U+22A5 in Unicode[1]) is a constant symbol used to represent:

The glyph of the up tack appears as an upside-down tee symbol, and as such is sometimes called eet (the word "tee" in reverse).[citation needed]

The tee (⊤), also called down tack, plays a complementary or dual role in many of these theories.

The similar-looking perpendicular symbol (, `\perp` in LaTeX, U+27C2 in Unicode) is a binary relation symbol used to represent: