A parody of the three laws of thermodynamics in terms of a person playing a game: (1) you can't win; (2) you can't break even; (3) you can't even get out of the game.

(group theory) A theorem which proves that, given a mind swap machine that can't be used on the same pair of people more than once, it is possible to reverse any number of mind swaps by introducing two more people that did not have their minds swapped with anyone before.

(politics) A theorem stating that no voting system can be perfectly fair in all circumstances

(logic) A theorem stating that, in any formal system F with Peano arithmetic, for any formula P, if it is provable in F that "if P is provable in F then P is true", then P is provable in F.

(mathematics) A theorem stating that any non-singular algebraic curve defined by algebraic number coefficients represents a compact Riemann surface which is a ramified covering of the Riemann sphere, ramified at three points only.

(economics) A theorem stating that, if trade in an externality is possible and there are sufficiently low transaction costs, bargaining will lead to a Pareto efficient outcome regardless of the initial allocation of property.

(group theory) The theorem stating that every group G is isomorphic to a subgroup of the symmetric group acting on G.

(quantum mechanics) A method of reducing high-order derivatives to a combinatorics problem, used extensively in quantum field theory to reduce arbitrary products of creation and annihilation operators to sums of products of pairs of these operators.

(computing theory) A theorem that establishes a limit on the extent to which an algorithm can decide whether certain mathematical expressions are equal.

(mathematics) A theorem stating that, if S, is an IP set and S=C_1∪C_2∪...∪C_n, then at least one C_i, contains an IP set.