Exhibit 10.1

AGREEMENT

     This Agreement (this “Agreement”) is made and entered into as of September
7, 2007, by and among Pershing Square, L.P., Pershing Square II, L.P. and
Pershing Square International, Ltd. (collectively the “Pershing Square Funds”),
and Ceridian Corporation, a Delaware corporation (“Ceridian”).

RECITALS

     A. Ceridian is scheduled to hold its annual meeting on September 12, 2007
(the “Annual Meeting”). The agenda for the Annual Meeting includes, among other
things, a vote on the merger (the “Merger”) contemplated by the Agreement and
Plan of Merger by and among Foundation Holdings, Inc., Foundation Merger Sub,
Inc. and Ceridian, dated as of May 30, 2007 and amended on July 30, 2007 (as so
amended, the “Merger Agreement”), and the election of the Ceridian board of
directors (the “Ceridian Board”).

     B. The Pershing Square Funds own in the aggregate 21,432,734 shares of
Ceridian common stock and have pending a proxy solicitation to elect their
proposed slate to the Ceridian Board.

     C. The Parties hereto agree that it is in the best interests of all
Ceridian stockholders to come to an amicable agreement with respect to the proxy
contest.

     NOW THEREFORE, the parties hereby agree as follows:

     1. The Pershing Square Funds and Ceridian and agree to issue the joint
press release in the form attached as Exhibit A.

     2. The Pershing Square Funds agree to terminate their proxy solicitation
and withdraw their nominations with respect to the Annual Meeting and to vote
all shares of Ceridian common stock beneficially owned by them in favor of the
Merger Agreement and the reelection of the current Ceridian Board’s nominees
(the “Incumbent Directors”).

     3. Ceridian agrees, and represents and warrants that the Ceridian Board has
agreed, that immediately after the Annual Meeting the Ceridian Board will take
all action necessary to increase the size of the Ceridian Board to eleven
members and to fill the four vacancies created by that increase with the
following people: John D. Barfitt, Paul C. Hilal, Robert J. Levenson and Gregory
A. Pratt (collectively, “Designated Directors”).

     4. Ceridian agrees, and represents and warrants that the Ceridian Board has
agreed, that between the time of the Annual Meeting and the earlier of the
closing of the Merger and the election and qualification of directors following
the Next Meeting referred to below, (a) the size of the Ceridian Board will not
be increased beyond eleven members, (b) other than (i) the Designated Directors
added pursuant to (3) above, (ii) replacements for Designated Directors selected
by the Pershing Square Funds and (iii) replacements for Incumbent Directors
selected by the remaining Incumbent Directors, no new Board members

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will be added to the Ceridian Board, and (c) at least one Designated Director
will be given the opportunity to join each committee of the Ceridian Board.

     5. Ceridian agrees, and represents and warrants that the Ceridian Board has
agreed, that in the event the Merger Agreement is terminated, during the period
between the time of termination of the Merger Agreement and the election and
qualification of directors following the Next Meeting referred to below,
Ceridian shall not, without the approval of a majority of the Ceridian Board
that includes the approval of two of the Designated Directors (the “Special
Approval”), take any action that would require the approval of the Ceridian
Board or any committee thereof pursuant to the Delegation of Authority attached
hereto as Exhibit B (the “Delegation of Authority”); provided that during such
period if the amount of any items covered by Sections I, II, III and XII under
the heading “Expenditure & Commitment Approvals” in the Delegation of Authority
exceeds $25 million in the aggregate in excess of amounts contemplated by
Ceridian’s previously approved capital plan, such items shall require the
Special Approval; and provided, further, that during such period any action
prohibited by Sections 5.1(b)(i) (other than cash dividends), 5.1(b)(ii),
5.1(b)(vi) (other than for employee compensation in the ordinary course of
business) or 5.1(b)(vii) of the Merger Agreement shall require the Special
Approval. For purposes of the second proviso of the preceding sentence, (a) the
Merger Agreement will be deemed to remain in effect even though in the
circumstances contemplated by that proviso it shall have been terminated and (b)
no effect will be given to any waivers, amendments or consents that Parent may
have agreed to in the past or agree to in the future. Notwithstanding the
foregoing, the nomination of a slate of directors for election at the Next
Meeting shall require only a simple majority approval of the Ceridian Board and
shall not require the Special Approval.

     6. Ceridian agrees, and represents and warrants that the Ceridian Board has
agreed, that in the event the Merger Agreement is terminated, (a) Ceridian will
hold the 2008 Annual Meeting of Stockholders or a special meeting of
stockholders (either such meeting, the “Next Meeting”) as soon as possible and
in any event within 90 calendar days after such termination to vote on the
election of the entire board of directors of Ceridian and (b) the then current
directors of Ceridian will take all actions necessary to facilitate such
election.

     7. The parties to this Agreement agree that irreparable damage would occur
if any provision of this Agreement were not strictly performed in accordance
with its terms and that each party to this Agreement shall be entitled to an
injunction to prevent breaches of this Agreement and to enforce specifically the
performance of the provisions hereof in any federal court located in Delaware or
in any Delaware state court, in addition to any other remedy to which any party
may be entitled at law or in equity.

     8. The parties to this Agreement agree that any suit, action or proceeding
to enforce any provision of, or based on any matter arising out of or in
connection with, this Agreement may be brought only in a federal court located
in Delaware or in any Delaware state court, and each party irrevocably consents
to the jurisdiction of such courts (and of the appellate courts therefrom) in
any such suit, action or proceeding and irrevocably waives any objection it may
now or hereafter have to the laying of venue of any such suit, action or

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proceeding in any such court or that any such suit, action or proceeding brought
in any such court has been brought in an inconvenient forum.

     9. This Agreement shall be governed by and construed in accordance with the
laws of the State of Delaware without giving effect to any conflict of law rules
that would otherwise cause the application of the laws of any other state.

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the day and year first above written.

CERIDIAN CORPORATION      By:  /s/ Kathryn V.
Marinello                                        Name:  Kathryn V. Marinello    
     Title:  President and Chief Executive Officer   PERSHING SQUARE, L.P.  By:
Pershing Square GP, LLC,                     its General Partner      By:  /s/
William A. Ackman                                           Name: William A.
Ackman           Title: Managing Member    PERSHING SQUARE II, L.P.  By:
Pershing Square GP, LLC,                     its General Partner      By:  /s/
William A. Ackman                                            Name: William A.
Ackman           Title: Managing Member    PERSHING SQUARE INTERNATIONAL, LTD. 
By: Pershing Square Capital Management, L.P                     its Investment
Manager  By: PS Management GP, LLC                     its Investment Manager   
  By:  /s/ William A. Ackman                                            Name:
William A. Ackman           Title: Managing Member 

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