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On two special classes of parallelohedra in E 6
Author(s) -
Engel P.
Publication year - 2019
Publication title -
acta crystallographica section a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.742
H-Index - 83
ISSN - 2053-2733
DOI - 10.1107/s2053273319001359
Subject(s) - sigma , group (periodic table) , cone (formal languages) , mathematics , combinatorics , quadratic equation , pure mathematics , physics , crystallography , chemistry , quantum mechanics , geometry , algorithm
The cone of positive‐definite quadratic forms is subdivided into aggregates of parallelohedra having certain properties. In E 6 , the Σ‐subcones are investigated and, in particular, the Σ 0 ‐subcone will be described which first occurs in E 6 and which is governed by the group . Further the ‐subcone which is governed by the group will be discussed for d = 6.