Whitehead group in mathematics may mean:
- A group W with Ext(W, Z)=0; see Whitehead problem
- For a ring, the Whitehead group Wh(A) of a ring A, equal to
- For a group, the Whitehead group Wh(G) of a group G, equal to K1(Z)/{±G}. Note that this is a quotient of the Whitehead group of the group ring.
- The Whitehead group Wh(A) of a simplicial complex or PL-manifold A, equal to Wh(π1(A)); see Whitehead torsion.
All named after J. H. C. Whitehead.
Famous quotes containing the words whitehead and/or group:
“If a dog jumps into your lap it is because he is fond of you; but if a cat does the same thing it is because your lap is warmer.”
—Alfred North Whitehead (1861–1947)
“Just as a person who is always asserting that he is too good-natured is the very one from whom to expect, on some occasion, the coldest and most unconcerned cruelty, so when any group sees itself as the bearer of civilization this very belief will betray it into behaving barbarously at the first opportunity.”
—Simone Weil (1910–1943)