Unbundling 3 theorems
Unbundling 3 theorems

- ~ ovmpt3rab1 and ~  elovmpt3rab1 revised using implicit substitution
  - problematic set variables not existing/needed anymore
- ~ 2wlkeq split into two variants:
  - ~ 2wlkeq ("degenerated instance")
  - ~ 2wlkeqdv ("principal instance")

metamath/set.mm,metamath/set.mm,metamath/set.mm