Suppose that \(L\) is a subset of \(I^{*},\) where \(I\) is a nonempty set of
symbols. If \(x \in I^{*},\) we let \(L / x=\left\\{z \in I^{*} | x z \in
L\right\\} .\) We say that the strings \(x \in I^{*}\) and \(y \in I^{*}\) are
distinguishable with respect to \(L\) if \(L / x \neq L / y .\) A string \(z\) for
which \(x z \in L\) but \(y z \notin L,\) or \(x z \notin L,\) but \(y z \in L\) is
said to distinguish \(x\) and \(y\) with respect to \(L .\) When \(L / x=L / y,\) we
say that \(x\) and \(y\) are indistinguishable with respect to \(L .\)
$$
\begin{array}{l}{\text { Let } L \text { be the set of all bit strings that
end with } 01 . \text { Show }} \\ {\text { that } 11 \text { and } 10 \text
{ are distinguishable with respect to } L \text { and }} \\ {\text { that the
strings } 1 \text { and } 11 \text { are indistinguishable with re- }} \\\
{\text { spect to } L .}\end{array}
$$