Proof Management Tool

Related projects
- Proof display
  - SETHEO proof trees
  - TRAMP
  - IMP
  - ILF tree viewer
- Proof storage and management
  - ProofPad (in ILF, but not available now)
  - Mizar
  - HELM
  - Proof General
- Omega stuff
- Verifiers
  - IVY
  - Bliksem's