(computing theory) Both NP-easy and NP-hard.

(law) The advantage, allowed to a mortgager, of a certain or reasonable time to redeem lands mortgaged, after they have been forfeited at law by the non-payment of the sum of money due on the mortgage at the appointed time.

(electronics) a logic gate performing a Boolean logic equivalence operation; an XNOR gate.

(mathematics) Any first-order ordinary differential equation that is quadratic in the unknown function.

(physics) An equation that attempts to meld the ideas of quantum mechanics and general relativity. It describes the quantum version of the Hamiltonian constraint using metric variables.

The amount of energy released by an explosion expressed in terms of the amount of TNT needed to generate a similar explosion. Used especially to describe nuclear bombs.

(logic) A relation between two structures which have the property that every first-order formula is valid in one structure if and only if it is valid in the other.

The equilibrium of allele and genotype frequencies postulated by the Hardy-Weinberg principle.

Abbreviation of equipment.

Abbreviation of equipment.