Pi v. Delta

pie.pngIn law student notes, plaintiffs are commonly denoted by π, and defendants by Δ. Even as I slavishly replicated this tradition as a student, I never understood it. Why are plaintiffs associated with “infinite . . . expansion . . . an irrational . . . indeed, a transcendental . . . expression“? And defendants a symbol variously matched with a proofreading symbol for deletion, the difference operator, and baryons?

Paging Nate Oman: a neat history of law problem to answer!

Update: An actual case suggests the practice is old. Pi v. Delta, 175 Conn. 527, 534, 400 A.2d 709 (1978) was a strange habeas proceeding for custody of a child. The case name is, alas, a fiction:

Upon the suggestion of the parties and in accordance with the spirit and intent of the order of the Superior Court granting the plaintiff’s motion to substitute fictitious names, it is ordered that the names of the parties involved in this appeal shall not be disclosed and that the records and briefs shall not be distributed to the various libraries of the state by the Reporter of Judicial Decisions. The records and papers of this case shall be open for inspection only to persons having a proper interest therein and upon order of this court.

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4 Responses

  1. I was under the impression that the usual abbeviation for plaintiff was Π rather than &pi — at least, all of the examples I’ve seen written out on blackboards used it. (Me, I just write P and D when time or space is short.) The upper case is consistent with the use of Δ rather than δ.

  2. Bruce Boyden says:

    Yeah, what a trial that was too. Pi’s counsel never finished her opening statement, which went on and on irrationally while never repeating. Delta’s counsel just kept reminiscing about how things used to be…

  3. Nate Oman says:

    I had always assumed that it was because pi makes a p sound as in “plaintiff” and delta makes a d sound as in “defendant” and lawyers are fond of pointless pseudo-erudition as in “res ipsa loquitor.” I know that I am certainly fond of pointless pseudo-erudition.

  4. shamu says:

    i also think that pseudo-erudition is the cause, namely as part of a concerted attempt in the early-mid 20th century to stack up to the ‘hard’ sciences.