11 U.S.C. § 502 : US Code - Section 502: Allowance of claims or interests

      (a) A claim or interest, proof of which is filed under section
    501 of this title, is deemed allowed, unless a party in interest,
    including a creditor of a general partner in a partnership that is
    a debtor in a case under chapter 7 of this title, objects.
      (b) Except as provided in subsections (e)(2), (f), (g), (h) and
    (i) of this section, if such objection to a claim is made, the
    court, after notice and a hearing, shall determine the amount of
    such claim in lawful currency of the United States as of the date
    of the filing of the petition, and shall allow such claim in such
    amount, except to the extent that - 
        (1) such claim is unenforceable against the debtor and property
      of the debtor, under any agreement or applicable law for a reason
      other than because such claim is contingent or unmatured;
        (2) such claim is for unmatured interest;
        (3) if such claim is for a tax assessed against property of the
      estate, such claim exceeds the value of the interest of the
      estate in such property;
        (4) if such claim is for services of an insider or attorney of
      the debtor, such claim exceeds the reasonable value of such
      services;
        (5) such claim is for a debt that is unmatured on the date of
      the filing of the petition and that is excepted from discharge
      under section 523(a)(5) of this title;
        (6) if such claim is the claim of a lessor for damages
      resulting from the termination of a lease of real property, such
      claim exceeds - 
          (A) the rent reserved by such lease, without acceleration,
        for the greater of one year, or 15 percent, not to exceed three
        years, of the remaining term of such lease, following the
        earlier of - 
            (i) the date of the filing of the petition; and
            (ii) the date on which such lessor repossessed, or the
          lessee surrendered, the leased property; plus

          (B) any unpaid rent due under such lease, without
        acceleration, on the earlier of such dates;

        (7) if such claim is the claim of an employee for damages
      resulting from the termination of an employment contract, such
      claim exceeds - 
          (A) the compensation provided by such contract, without
        acceleration, for one year following the earlier of - 
            (i) the date of the filing of the petition; or
            (ii) the date on which the employer directed the employee
          to terminate, or such employee terminated, performance under
          such contract; plus

          (B) any unpaid compensation due under such contract, without
        acceleration, on the earlier of such dates;

        (8) such claim results from a reduction, due to late payment,
      in the amount of an otherwise applicable credit available to the
      debtor in connection with an employment tax on wages, salaries,
      or commissions earned from the debtor; or
        (9) proof of such claim is not timely filed, except to the
      extent tardily filed as permitted under paragraph (1), (2), or
      (3) of section 726(a) of this title or under the Federal Rules of
      Bankruptcy Procedure, except that a claim of a governmental unit
      shall be timely filed if it is filed before 180 days after the
      date of the order for relief or such later time as the Federal
      Rules of Bankruptcy Procedure may provide, and except that in a
      case under chapter 13, a claim of a governmental unit for a tax
      with respect to a return filed under section 1308 shall be timely
      if the claim is filed on or before the date that is 60 days after
      the date on which such return was filed as required.

      (c) There shall be estimated for purpose of allowance under this
    section - 
        (1) any contingent or unliquidated claim, the fixing or
      liquidation of which, as the case may be, would unduly delay the
      administration of the case; or
        (2) any right to payment arising from a right to an equitable
      remedy for breach of performance.

      (d) Notwithstanding subsections (a) and (b) of this section, the
    court shall disallow any claim of any entity from which property is
    recoverable under section 542, 543, 550, or 553 of this title or
    that is a transferee of a transfer avoidable under section 522(f),
    522(h), 544, 545, 547, 548, 549, or 724(a) of this title, unless
    such entity or transferee has paid the amount, or turned over any
    such property, for which such entity or transferee is liable under
    section 522(i), 542, 543, 550, or 553 of this title.
      (e)(1) Notwithstanding subsections (a), (b), and (c) of this
    section and paragraph (2) of this subsection, the court shall
    disallow any claim for reimbursement or contribution of an entity
    that is liable with the debtor on or has secured the claim of a
    creditor, to the extent that - 
        (A) such creditor's claim against the estate is disallowed;
        (B) such claim for reimbursement or contribution is contingent
      as of the time of allowance or disallowance of such claim for
      reimbursement or contribution; or
        (C) such entity asserts a right of subrogation to the rights of
      such creditor under section 509 of this title.

      (2) A claim for reimbursement or contribution of such an entity
    that becomes fixed after the commencement of the case shall be
    determined, and shall be allowed under subsection (a), (b), or (c)
    of this section, or disallowed under subsection (d) of this
    section, the same as if such claim had become fixed before the date
    of the filing of the petition.
      (f) In an involuntary case, a claim arising in the ordinary
    course of the debtor's business or financial affairs after the
    commencement of the case but before the earlier of the appointment
    of a trustee and the order for relief shall be determined as of the
    date such claim arises, and shall be allowed under subsection (a),
    (b), or (c) of this section or disallowed under subsection (d) or
    (e) of this section, the same as if such claim had arisen before
    the date of the filing of the petition.
      (g)(1) A claim arising from the rejection, under section 365 of
    this title or under a plan under chapter 9, 11, 12, or 13 of this
    title, of an executory contract or unexpired lease of the debtor
    that has not been assumed shall be determined, and shall be allowed
    under subsection (a), (b), or (c) of this section or disallowed
    under subsection (d) or (e) of this section, the same as if such
    claim had arisen before the date of the filing of the petition.
      (2) A claim for damages calculated in accordance with section 562
    shall be allowed under subsection (a), (b), or (c), or disallowed
    under subsection (d) or (e), as if such claim had arisen before the
    date of the filing of the petition.
      (h) A claim arising from the recovery of property under section
    522, 550, or 553 of this title shall be determined, and shall be
    allowed under subsection (a), (b), or (c) of this section, or
    disallowed under subsection (d) or (e) of this section, the same as
    if such claim had arisen before the date of the filing of the
    petition.
      (i) A claim that does not arise until after the commencement of
    the case for a tax entitled to priority under section 507(a)(8) of
    this title shall be determined, and shall be allowed under
    subsection (a), (b), or (c) of this section, or disallowed under
    subsection (d) or (e) of this section, the same as if such claim
    had arisen before the date of the filing of the petition.
      (j) A claim that has been allowed or disallowed may be
    reconsidered for cause. A reconsidered claim may be allowed or
    disallowed according to the equities of the case. Reconsideration
    of a claim under this subsection does not affect the validity of
    any payment or transfer from the estate made to a holder of an
    allowed claim on account of such allowed claim that is not
    reconsidered, but if a reconsidered claim is allowed and is of the
    same class as such holder's claim, such holder may not receive any
    additional payment or transfer from the estate on account of such
    holder's allowed claim until the holder of such reconsidered and
    allowed claim receives payment on account of such claim
    proportionate in value to that already received by such other
    holder. This subsection does not alter or modify the trustee's
    right to recover from a creditor any excess payment or transfer
    made to such creditor.
      (k)(1) The court, on the motion of the debtor and after a
    hearing, may reduce a claim filed under this section based in whole
    on an unsecured consumer debt by not more than 20 percent of the
    claim, if - 
        (A) the claim was filed by a creditor who unreasonably refused
      to negotiate a reasonable alternative repayment schedule proposed
      on behalf of the debtor by an approved nonprofit budget and
      credit counseling agency described in section 111;
        (B) the offer of the debtor under subparagraph (A) - 
          (i) was made at least 60 days before the date of the filing
        of the petition; and
          (ii) provided for payment of at least 60 percent of the
        amount of the debt over a period not to exceed the repayment
        period of the loan, or a reasonable extension thereof; and

        (C) no part of the debt under the alternative repayment
      schedule is nondischargeable.

      (2) The debtor shall have the burden of proving, by clear and
    convincing evidence, that - 
        (A) the creditor unreasonably refused to consider the debtor's
      proposal; and
        (B) the proposed alternative repayment schedule was made prior
      to expiration of the 60-day period specified in paragraph
      (1)(B)(i).