Extended real arithmetic (was Re: inf - inf = 0 ??)



Richard Hennessy wrote:

"Clearly limit(sin(x),x,inf)=>IND and IND-IND must be IND"

The first statement is clear, the second is not.  Can you prove
it?

Well, that statement is clearly wrong, because for any expr with
limit(expr(x),x,a) => IND we  obviously have  limit(expr(x),x,a) -
limit(expr(x),x,a)  = limit(expr(x)-expr(x),x,a) = limit(0,x,a) =
0.

Andreas
-- 
ceterum censeo redmondinem esse delendam.