Theorem truxortru

A \/_ identity. (Contributed by David A. Wheeler, 8-May-2015.)

Conclusion
\( \vdash \top \veebar \top \leftrightarrow \bot \)
Proof
l0
df-xor
\( \vdash \top \veebar \top \leftrightarrow \neg (\top \leftrightarrow \top) \)
trubitru
\( \vdash \top \leftrightarrow \top \leftrightarrow \top \)
l2
xchbinx l0 _
\( \vdash \top \veebar \top \leftrightarrow \neg \top \)
nottru
\( \vdash \neg \top \leftrightarrow \bot \)
bitri l2 _