Building on work of Huntington (1933), Robbins conjectured that the equations for a Robbins algebra, commutativity,
associativity, and the Robbins Equation

imply those for a Boolean Algebra. The conjecture was finally proven using a computer (McCune 1997).

**References**

Huntington, E. V. ``New Sets of Independent Postulates for the Algebra of Logic, with Special Reference
to Whitehead and Russell's *Principia Mathematica.*'' *Trans. Amer. Math. Soc.* **35**, 274-304, 1933.

Huntington, E. V. ``Boolean Algebra. A Correction.'' *Trans. Amer. Math. Soc.* **35**, 557-558, 1933.

McCune, W. ``Solution of the Robbins Problem.'' *J. Automat. Reason.* **19**, 263-276, 1997.

McCune, W. ``Robbins Algebras are Boolean.'' http://www-unix.mcs.anl.gov/~mccune/papers/robbins/.

Nelson, E. ``Automated Reasoning.'' http://www.math.princeton.edu/~nelson/ar.html.

© 1996-9

1999-05-25