Some articles on van, diagrams, van kampen diagram:
... There are several generalizations of van-Kampen diagrams where instead of being planar, connected and simply connected (which means being homotopically equivalent to a disk) the ... A particularly important one of these is the notion of an annular van Kampen diagram, which is homotopically equivalent to an annulus ... Annular diagrams, also known as conjugacy diagrams, can be used to represent conjugacy in groups given by group presentations ...
Famous quotes containing the words diagrams and/or van:
“Professors could silence me then; they had figures, diagrams, maps, books.... I was learning that books and diagrams can be evil things if they deaden the mind of man and make him blind or cynical before subjection of any kind.”
—Agnes Smedley (18901950)
“... two men could be just alike in all their dispositions to verbal behavior under all possible sensory stimulations, and yet the meanings or ideas expressed in their identically triggered and identically sounding utterances could diverge radically, for the two men, in a wide range of cases.”
—Willard Van Orman Quine (b. 1908)