Stream: Beginner Questions

Topic: Rotation premises of a specific subgoal


view this post on Zulip Hanno Becker (Apr 22 2023 at 15:28):

Hi! Is there a tactic/conversion in the stdlib to rotate the pure assumptions of a subgoal? (Motivation: I'd like to have an index-based version of thin_tac and want to rotate the premise-to-be-removed to the front first, and then drop it via Pure.thin_rl) The kernel has a helper for rotating subgoals themselves, but I don't see how to get from there to rotating the premises of a subgoal.

view this post on Zulip Kevin Kappelmann (Apr 22 2023 at 17:30):

You are looking for rotate_tac:

ML
  fun thin_tac i = rotate_tac i THEN' eresolve0_tac [thin_rl] THEN' rotate_tac (~i)


lemma "P x ⟹ Q x ⟹ C" and "⋀x. P' x ⟹ Q' x ⟹ C'"
  apply -
  apply (tactic ‹rotate_tac 1 1›) (*works*)
  apply (tactic ‹rotate_tac 1 2›) (*works*)
  apply (tactic ‹thin_tac 0 1›) (*works*)
  apply (tactic ‹thin_tac 1 2›) (*works*)
  oops

view this post on Zulip Wolfgang Jeltsch (Apr 22 2023 at 17:31):

There’s also the rotated attribute. Not sure how relevant this is to you use case.

view this post on Zulip Hanno Becker (Apr 22 2023 at 18:22):

Ah, great. Not sure how I missed that :rolling_eyes: Thank you!


Last updated: Dec 21 2024 at 16:20 UTC