\DOC REV_SUPPOSE_TAC
\TYPE
{
REV_SUPPOSE_TAC : term -> tactic
}
\LIBRARY utils
\SYNOPSIS
A tactic for adding an assumption to a goal, with the condition
that the assumption be proved first.
\DESCRIBE
The tactic {REV_SUPPOSE_TAC t} when applied to a goal
{([a1,...,an],Goal)}
returns the two subgoals
{
([a1,...,an],t)
([t,a1,...,an],Goal)
}
\noindent The differnce between {REV_SUPPOSE_TAC} and {SUPPOSE_TAC} is
the
order in which they return the subgoals.
\FAILURE
The tactic {REV_SUPPOSE_TAC} fails if it is not given a term of type
{(==`:bool`==)}.
\EXAMPLE
{
SUPPOSE_TAC (--`?n. INT n = MIN`--)
}
\noindent when applied to the goal
{
([(--`POS MIN`--)], (--`?x:num. Y = ((MAX times (INT x)) plus REM)`-))
}
returns the two subgoals
{
([(--`POS MIN`--)], (--`?n. INT n = MIN`--))
([(--`?n. INT n = MIN`--), (--`POS MIN`--)],
(--`?x. Y = ((MAX times (INT x)) plus REM)`--))
}
\USES
Adding lemmas as assumptions to a goal to assists in its proof.
{REV_SUPPOSE_TAC} allows you to inline the proof of a fairly short easy
lemma while proving a theorem using the goal stack, and then return to
your
original proof with the lemma available as an assumption.
\SEEALSO
{
SUPPOSE_TAC, ASSUME_TAC
}
\ENDDOC