Proof step

Liu–Wang theorem for three-term recurrences

Theorem check of the sequence's own rule liu wang three term

Concludes: Riordan array (1, x/(1-3*x+2*x^2)).
Premises: none: a direct theorem check
Theorem: [LW07, Thm 2.1, Thm 2.3, Cor 2.4, Prop 3.3] polytool ?
Lean: RealRooted route sign RealRooted.threeTerm_interlaces_of_eval_nonpos, RealRooted.threeTerm_interlaces, RealRooted.eval_nonpos_of_natDegree_le_two
Checked: polytool replayed · Lean not attempted

Technical details

Step id

e-2d1e5381bf0c7c76 · JSON

Operation

Theorem check of the sequence's own rule

{
  "operation": "theorem_check",
  "theorem": "liu_wang_three_term"
}

Claims

{
  "claim": "real_rooted",
  "from_index": 0,
  "region": {
    "upper": {
      "closed": true,
      "value": "0"
    }
  }
}

{
  "claim": "interlacing",
  "from_index": 2,
  "kind": "weak",
  "orientation": "previous_interlaces_next"
}

Certificate

theorem_check, SHA-256 a21a01acb424176057fc7cf69b4125fefe4bbb2e52470573b659fdda6fd66094, 5,344 bytes (1,679 compressed); download

polytool replayed the certificate when the step was written.

Cited by

References

[LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003