Exact expanded PA statement
forall a b c d. (a + b) + (c + d) = (c + b) + (a + d)Structural proof guide
Generated structural guide
Permute the outer entries of two additive pairs.
Use the direct prerequisites add_assoc, add_comm as previously established PA formulas.
The proof proceeds by direct introduction and elimination.
Referenced ingredients
Proof neighborhood
Direct dependencies
Direct dependents
Formal native tactic body
Dependencies are introduced as named hypotheses before line 1. Linked names are exact direct references. This Stable checked-use theorem is independently kernel-checked when replayed.
- 0001
intro a - 0002
intro b - 0003
intro c - 0004
intro d - 0005
trans a + (b + (c + d)) - 0006
apply add_assoc - 0007
trans a + ((b + c) + d) - 0008
congr - 0009
refl - 0010
symm - 0011
apply add_assoc - 0012
trans a + ((c + b) + d) - 0013
congr - 0014
refl - 0015
congr - 0016
apply add_comm - 0017
refl - 0018
trans (a + (c + b)) + d - 0019
symm - 0020
apply add_assoc - 0021
trans ((c + b) + a) + d - 0022
congr - 0023
apply add_comm - 0024
refl - 0025
apply add_assoc