** The Nielsen – Schreier theorem, that every subgroup of a free group is free.

** Carefree means " free from care or anxiety.

** Carefree means ' free from care or anxiety '.

** Mini Zork I: The Great Underground Empire ( 1987, Marc Blank & Dave Lebling, free cut-down, single load tape version of game, covermounted on UK's ZZAP! 64 magazine )

** Freeview digital free satellite with a dozen SD channels, with SD feeds of the terrestrial HD freeview channels.

** Sex drive is dependent on androgen levels only in the presence of estrogen, but without estrogen, free testosterone level actually decreases sexual desire ( instead of increases sex drive ), as demonstrated for those women who have hypoactive sexual desire disorder, and the sexual desire in these women can be restored by administration of estrogen ( using oral contraceptive ).

** the free product of groups

** Webs ( web hosting ), a website which allows users to create free websites

** Raid at Cabanatuan: 121 American soldiers and 800 Filipino guerrillas free 813 American POWs from the Japanese-held camp at Cabanatuan City, Philippines.

** Cold War: East Germany holds its first free elections.

** Gulf War: The United Nations Security Council passes UN Security Council Resolution 678, authorizing military intervention in Iraq if that nation does not withdraw its forces from Kuwait and free all foreign hostages by Tuesday, January 15, 1991.

** Entebbe Raid: Israeli airborne commandos free 103 hostages being held by Palestinian hijackers of an Air France plane at Uganda's Entebbe Airport ; 1 Israeli soldier and several Ugandan soldiers are killed in the raid.

** The first free parliamentary elections are held in Poland.

** Kidnappers in Lebanon set Anglican Church envoys Terry Waite and Thomas Sutherland free.

** First free flight of Igor Sikorsky's Vought-Sikorsky VS-300 helicopter.

** Vietnam War – Operation Ivory Coast: A joint Air Force and Army team raids the Son Tay prison camp in an attempt to free American POWs thought to be held there ( no Americans are killed, but the prisoners have already moved to another camp ; all U. S. POWs are moved to a handful of central prison complexes as a result of this raid ).

** In Chipping Norton, England rioters attempt to free the Ascott Martyrs – sixteen women sentenced to imprisonment for attempting to dissuade strikebreakers.

** The Soviet manned space mission Soyuz 18a ends in failure during its ascent into orbit when a critical malfunction occurs in the second and third stages of the booster rocket during staging, resulting with the cosmonauts and their Soyuz spacecraft having to be ripped free from the vehicle.

** Brazil holds the second round of its first free election in 29 years ; Fernando Collor de Mello wins.

** Richard Stallman, American free software proponent

** 86 free African American colonists sail from New York City to Freetown, Sierra Leone.

** The Dutch were for free trade, while industries in Belgium called for the protection of tariffs.

** GnuTLS, free software implementation of the SSL and TLS protocols

** admitted California as a free state

** If S is a set of sentences of first-order logic and B is a consistent subset of S, then B is included in a set that is maximal among consistent subsets of S. The special case where S is the set of all first-order sentences in a given signature is weaker, equivalent to the Boolean prime ideal theorem ; see the section " Weaker forms " below.

** Stone's representation theorem for Boolean algebras needs the Boolean prime ideal theorem.

** Parity function, a Boolean function whose value is 1 if the input vector has an odd number of ones

** The application of Boolean Algebra to relay circuit design was formalized by Claude Shannon in A Symbolic Analysis of Relay and Switching Circuits

** Boolean circuit

** Boolean algebra ( structure )

** vector algebra and vector differential operators

** Linear algebra explains how a vector space can be given a basis, and then any vector can be expressed in this basis.

** Term algebra, the algebra of mathematical terms

** Torsion ( algebra )

** Projection ( relational algebra )

** Projection ( linear algebra )

** Join ( relational algebra ), a type of binary operator

** Join ( sigma algebra ), a refinement of sigma algebras

** free associative algebra

** free commutative algebra

** free Heyting algebra

** Frobenius algebra

** Goodman – Nguyen – van Fraassen algebra

** The fundamental theorem of algebra, a theorem regarding the factorization of polynomials

** Analytic geometry, the study of geometry using the principles of algebra

** Linear algebra

** eigen, a C ++ linear algebra library, includes an adaptation of the minpack algorithm in the " NonLinearOptimization " module.

** Borel measure, the measure on a Borel algebra

** Householder transformation in geometry and linear algebra

** When talking about indefinite forms in multilinear algebra, see definite bilinear form.

** Dimension ( vector space ), the number of vectors needed to describe the basis in a vector space, in linear algebra

** Abstract algebra stubs:

** Linear algebra stubs: