BT010C · Bertrand theorem

three_mul_le_square_of_three_le

Alpha v34 checked-use theorem · independently kernel and Lean verified; not Stable

Every natural at least three dominates three times itself by its square.

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

∀ s. Lt(2,s)Le(3 · s,s · s)

Every purple notation token opens its conservative definition. Expanding the displayed statement recovers the exact first-order Peano-arithmetic formula checked by the unchanged kernel.

Definitions used by this theorem

In the theorem statement

2 occurrences

In local proof propositions

none

0 occurrences

Exact expanded native-PA statement
forall s. (exists bcf_le_gap_b5rbtmsts_source. bcf_le_gap_b5rbtmsts_source + (3) = s) -> (exists bcf_le_gap_b5rbtmsts_result. bcf_le_gap_b5rbtmsts_result + (3 * s) = s * s)

Proof neighborhood

Direct theorem prerequisites

Direct theorem dependents

Definition-aware tactic body

Only local propositions introduced by have or suffices are compacted. Every changed line has an exact-AST conservative-expansion receipt; the kernel still receives the immutable original tactic script.

Read the argument

Proof checkpoints

7 script commands · 2 reading checkpoints · 0 local claims

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.

Definition notation is shown below. Open the paired exact edition for the original native formulas. Source pairing is not a new equivalence certificate.

Named ingredients (1)
01Fix variables and assumptionsL1–2

Work with arbitrary variables or the premises of the current implication.

  1. L1
    intro s
  2. L2
    intro hthree
02Use earlier factsL3–7

Instantiate or apply named facts and discharge the corresponding proof obligations.

  1. L3
    specialize mul_le_mul_right 3
  2. L4
    specialize mul_le_mul_right s
  3. L5
    specialize mul_le_mul_right s
  4. L6
    apply mul_le_mul_right
  5. L7
    exact hthree

Library-wide reading audit

Original defined command ledger · 7 lines
  1. 0001intro s
  2. 0002intro hthree
  3. 0003specialize mul_le_mul_right 3
  4. 0004specialize mul_le_mul_right s
  5. 0005specialize mul_le_mul_right s
  6. 0006apply mul_le_mul_right
  7. 0007exact hthree