Definition of "nilpotent" []

• An algebraic quantity that when raised to a certain power equals zero. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "There is nothing inconsistent with this restriction, and the positive L_m in isolation generate a gauge symmetry; there is no anomaly in the positive sector and thus a nilpotent BRST operator."
• "Hence this subalgebra admits a nilpotent BRST operator, and can be viewed as a gauge symmetry."
• "The BRST operator for the full Virasoro algebra is not nilpotent, and hence a global symmetry."