Current library: Alpha v34, 4,223 checked-use theorems; Stable remains 432. Historical first admissions, original proof editions, and non-admitted aliases are preserved. Exact original first-admission records.
Statement with defined notation
forall a c. exists x. (((a) = (c) + (x) \/ (c) = (a) + (x)))Every purple notation token opens its conservative definition. This reading surface never changes the unchanged intuitionistic kernel or confers checked-use authority.
Definitions used by this theorem
In the theorem statement
In local proof propositions
Exact expanded first-order statement
forall a c. exists x. (((a) = (c) + (x) \/ (c) = (a) + (x)))Proof neighborhood
Direct theorem prerequisites
Direct theorem dependents
Definition-aware tactic body
Only propositions whose conservative expansion has been checked for exact first-order equivalence are compacted. Every changed line retains its immutable exact replay command.
Read the argument
Proof checkpoints
This is a reading aid, not a new proof or a proof-tree certificate. Checkpoint groups are consecutive commands, not inferred branch boundaries. Every step links to the preserved script.
01Fix variables and assumptionsL1–2
02Use earlier factsL3–4
03Separate the logical casesL5–6
04Construct an explicit witnessL7–7
Supply the displayed value, then prove that it has the required property.
- L7
exists x
05Separate the logical casesL8–8
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L8
right
06Calculate and transport equalitiesL9–10
07Use earlier factsL11–12
08Separate the logical casesL13–13
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L13
cases le_total_right
09Construct an explicit witnessL14–14
Supply the displayed value, then prove that it has the required property.
- L14
exists x
10Separate the logical casesL15–15
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L15
left
11Calculate and transport equalitiesL16–17
Original defined command ledger · 19 lines
- 0001
intro a - 0002
intro c - 0003
specialize le_total a - 0004
specialize le_total c - 0005
cases le_total - 0006
cases le_total_left - 0007
exists x - 0008
right - 0009
trans x + a - 0010
symm - 0011
exact le_total_left_witness - 0012
apply add_comm - 0013
cases le_total_right - 0014
exists x - 0015
left - 0016
trans x + c - 0017
symm - 0018
exact le_total_right_witness - 0019
apply add_comm