https://github.com/JacquesCarette/hol-light
Tip revision: b27a524086caf73530b7c2c5da1b237d3539f143 authored by Jacques Carette on 24 August 2020, 14:18:07 UTC
Merge pull request #35 from sjjs7/final-changes
Merge pull request #35 from sjjs7/final-changes
Tip revision: b27a524
CONTR.doc
\DOC CONTR
\TYPE {CONTR : term -> thm -> thm}
\SYNOPSIS
Implements the intuitionistic contradiction rule.
\KEYWORDS
rule, contradiction.
\DESCRIBE
When applied to a term {t} and a theorem {A |- F}, the inference rule {CONTR}
returns the theorem {A |- t}.
{
A |- F
-------- CONTR `t`
A |- t
}
\FAILURE
Fails unless the term has type {bool} and the theorem has {F} as its
conclusion.
\EXAMPLE
{
# let th = REWRITE_RULE[ARITH] (ASSUME `1 = 0`);;
val th : thm = 1 = 0 |- F
# CONTR `Russell:Person = Pope` th;;
val it : thm = 1 = 0 |- Russell = Pope
}
\SEEALSO
CCONTR, CONTR_TAC, NOT_ELIM.
\ENDDOC