--- a/NEWS Mon May 08 11:45:57 2000 +0200
+++ b/NEWS Mon May 08 16:57:53 2000 +0200
@@ -115,9 +115,13 @@
basically a generalized version of de-Bruijn representation; very
useful in avoiding lifting all operations;
-* greatly improved simplification involving numerals of type "nat", e.g.
+* greatly improved simplification involving numerals of type nat & int, e.g.
(i + #8 + j) = Suc k simplifies to #7 + (i + j) = k
- i*j + k + j*#3*i simplifies to #4*(i*j) + k;
+ i*j + k + j*#3*i simplifies to #4*(i*j) + k
+ two terms #m*u and #n*u are replaced by #(m+n)*u
+ (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
+ and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
+ or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
* new version of "case_tac" subsumes both boolean case split and
"exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer