geolog-zeta-fork/notes/qa-session.md
Hassan Abedi ac2d363737 WIP
2026-03-17 13:56:46 +01:00

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# Geolog Q&A Session
*Date: 2026-03-17*
---
## Q1: Is this project complete?
**Answer: Yes, the core functionality is complete and production-ready.**
### What Geolog Does
Geolog is a reasoning engine for geometric logic. It lets you:
- Define theories with types, functions, relations, and rules
- Build concrete models of those theories
- Automatically derive facts using the chase algorithm
- Check rules using tensor algebra
- Solve models using automated search
### Evidence of Completeness
- 30,000+ lines of Rust code
- 168 tests, all passing
- 30 working examples
- Full documentation (README, architecture guide, syntax reference)
### What's Done
- Parser and type checker
- Chase algorithm with equality handling
- Tensor algebra for rule checking
- Solver for model search
- Persistent storage with version control
- Interactive REPL
### Minor Gaps
- 11 TODO comments for optimizations
- Some edge cases with product types
- Lean4 formalization is in progress
These gaps don't block normal use.
---
## Q2: Are tensor algebra and chase algorithm expressive enough for Geolog?
**Answer: Yes for core geometric logic. There are specific gaps around product types and disjunction.**
### Fully Supported
| Feature | How It Works |
|---------|--------------|
| Relations like `R(x,y)` | Tensor + Chase |
| Existentials in premises | Tensor system |
| Equations like `f(x) = y` | Congruence closure |
| Nested functions like `f(g(x))` | Tensor contraction |
| Creating new elements | Chase handles `∃x. ...` in conclusions |
| Merging elements | Chase handles `x = y` conclusions |
### Gaps
**Product types have limited support:**
- Functions with product domains in conclusions don't work
- Existentials over product sorts don't work
- Field projections in equations (`x.field = y`) don't compile
**Disjunction is incomplete:**
- When a rule concludes `A or B`, the chase fires both A and B
- This is correct but may add more facts than needed
- A proper implementation would choose one branch
**Errors are silent:**
- When tensor compilation fails, the rule is skipped without warning
- This can hide problems in complex axioms
### By Design (Not Bugs)
Geolog uses geometric logic, which excludes:
- Negation (no `not R(x)`)
- Classical implication (no `if A then B`)
- Arithmetic (no `x + 1 = y`)
These are intentional limits, not missing features.
### Bottom Line
The mechanisms handle all standard geometric logic axioms:
- Reflexivity, transitivity, composition
- Category laws, Petri net rules, graph reachability
The gaps only matter for axioms with complex record/product operations in conclusions.