User-Machine Dialogues 2:

One of the most complex issues in our research is the relationship of
natural language  understanding ability to  programming ability.
In one respect, this was the major weakness of the PUP6 system.
A good strategy, when confronted by two complex issues, is to find
a domain in which only one of them presents itself. For this reason,
Lenat is now considering, as a task domain, programs doing research
in elementary mathematics. Although rich, the typical mathematics subset
of English seems quite manageable.
With communication both simple and rare, the major problems encountered
should be directly connected to code synthesis or to the domain itself.

Other tasks 2:

The central concept of PUP6 was that of uniformly maintaining all knowledge
as BEINGs, where each BEING has the same internal structure, yet where that
structure is quite intricate. "Automatic code synthesis" then reduces to
"writing new BEINGs", since the control structure is considered forever fixed.
The Automated Mathematician project now shifts the domain from concept
formation to elementary mathematics. Knowledge about mathematical concepts
is still represented procedurally, as parts of BEINGs. New knowledge is
added to the system by writing more code (more BEINGs); this demands some
code-writing knowledge and some mathematics-development knowledge.
This project will depend crucially on the code synthesis
techniques developed in the PUP6 system.