# Definition:Top (Logic)

## Definition

Top is a constant of propositional logic interpreted to mean the canonical, undoubted tautology whose truth nobody could possibly ever question.

The symbol used is $\top$.

## Boolean Interpretation

There is only one boolean interpretation for $\top$:

$v \left({\top}\right) = T$

where $T$ symbolises true.

## Truth Table

The characteristic truth table of the top constant $\top$ of propositional logic is as follows:

$\begin{array}{|c|} \hline \top \\ \hline T \\ \hline \end{array}$

## Also denoted as

Not all sources use the $\top$ symbol. Some use $\text T$ or a stylistic variant, and others write it longhand as $\text{true}$.

## Technical note

The $\LaTeX$ code for $\top$ is \top .