SBC_CONV : conv
STRUCTURE
reduceLib
SYNOPSIS
Calculates by inference the difference of two numerals.
LIBRARY
reduce
DESCRIPTION
If m and n are numerals (e.g. 0, 1, 2, 3,...), then SBC_CONV "m - n" returns the theorem: 
   |- m - n = s
where s is the numeral that denotes the difference of the natural numbers denoted by m and n.
FAILURE
SBC_CONV tm fails unless tm is of the form "m - n", where m and n are numerals.
EXAMPLE
#SBC_CONV "25 - 30";;
|- 25 - 30 = 0

#SBC_CONV "200 - 200";;
|- 200 - 200 = 0

#SBC_CONV "60 - 17";;
|- 60 - 17 = 43
HOL  Kananaskis-10