Firstly, some lemmas.
\statement{Tip Correct Contents}{
- \tipcy \haspatch \pd
+ \tipcy \haspatch \pa E
\equiv
- \pd = \pc \lor \pd \isdep \pc
+ \pa E = \pc \lor \pa E \isdep \pc
}
\proof{
- For $\pc = \pd$, Tip Own Contents suffices.
- For $\pc \neq \pd$, Exclusive Tip Contents
+ For $\pc = \pa E$, Tip Own Contents suffices.
+ For $\pc \neq \pa E$, Exclusive Tip Contents
gives $D \isin \tipcy \equiv D \isin \baseof{\tipcy}$
which by Correct Base $\equiv D \isin \tipcn$.
}