Around 1980, I caused thrashing on SRI&#x27;s DEC-20 by using the Boyer-Moore theorem prover. I was working on some theorems involving 16-bit arithmetic, and had numbers such as 65536.  Those were internally represented as (add1 (add1 (add1 ... (zero))))..., because Boyer-Moore theory is true constructive mathematics.  This used enough memory to cause paging.<p>Boyer and Moore put in an actual integer representation after that.  We got our own VAX at Ford Aerospace and ported the prover to that. Then we could get some work done on proof of correctness.