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unusual facts about Quillen's lemma


Quillen's lemma

In contrast to a version of Schur's lemma due to Dixmier, it does not require k to be uncountable.


Aronszajn tree

The existence of Aronszajn trees (=\aleph 1-Aronszajn trees) was proven by Nachman Aronszajn, and implies that the analogue of König's lemma does not hold for uncountable trees.

Burnside's lemma

Consequently, this lemma is sometimes referred to as the lemma that is not Burnside's.

By Now

"By Now" is the title of a song written by Dean Dillon, Don Pfrimmer and Charles Quillen, and recorded by American country music artist Steve Wariner.

Hensel's lemma

Masayoshi Nagata proved in the 1950s that for any commutative local ring A with maximal ideal m there always exists a smallest ring Ah containing A such that Ah is Henselian with respect to mAh.

Completeness of a ring is not a necessary condition for the ring to have the Henselian property: Goro Azumaya in 1950 defined a commutative local ring satisfying the Henselian property for the maximal ideal m to be a Henselian ring.

Hotelling

Hotelling's lemma: an economic rule relating the supply of a good to the profit of the good's producer

König's theorem

König's lemma (also known as König's infinity lemma), named after Dénes Kőnig

Leonid Vaseršteĭn

He is well known for providing a simple proof of the Quillen–Suslin theorem, a result in commutative algebra, first conjectured by Jean-Pierre Serre in 1955, and then proved by Daniel Quillen and Andrei Suslin in 1976.

Oka's lemma

In mathematics, Oka's lemma, proved by Kiyoshi Oka, states that in a domain of holomorphy in Cn, the function –log d(z) is plurisubharmonic, where d is the distance to the boundary.

Quillen–Suslin theorem

Leonid Vaseršteĭn later gave a simpler and much shorter proof of the theorem which can be found in Serge Lang's Algebra.

Robert Quillen

In 1934 Hollywood screen writer Lamar Trotti and producer George Marshall visited Quillen to use him as a prototype for a Will Rogers film, Life Begins at Forty, in which Rogers played a small-town newspaper editor.

Quillen wrote for such major periodicals such as the Baltimore Sun, the Saturday Evening Post, and The American Magazine, and he "took the greatest pride" in one-liners picked up by Literary Digest.

Schanuel's lemma

In mathematics, especially in the area of algebra known as module theory, Schanuel's lemma, named after Stephen Schanuel, allows one to compare how far modules depart from being projective.

Scheffé’s lemma

Henry Scheffé published a proof of the statement on convergence of probability densities in 1947.

Shephard's lemma

The lemma is named after Ronald Shephard who gave a proof using the distance formula in his book Theory of Cost and Production Functions (Princeton University Press, 1953).

Varghese Mathai

Using the superconnection formalism of Quillen, they obtained a refinement of the Riemann–Roch formula, which links together the Thom classes in K-theory and cohomology, as an equality on the level of differential forms.

Zorn's Law

Zorn's lemma is a proposition used in many areas of theoretical mathematics.

Zorn's lemma

# Banach's extension theorem which is used to prove one of the most fundamental results in functional analysis, the Hahn–Banach theorem

It occurs in the proofs of several theorems of crucial importance, for instance the Hahn–Banach theorem in functional analysis, the theorem that every vector space has a basis, Tychonoff's theorem in topology stating that every product of compact spaces is compact, and the theorems in abstract algebra that every nonzero ring has a maximal ideal and that every field has an algebraic closure.


see also