English

Alternative forms

• semi-direct

Adjective

semidirect ‎(not comparable)

1. Neither unqualifiedly direct nor unqualifiedly indirect.
   • 1984, I. Berqvist, Chapter II: Fast Neutron Radiative Capture, B. J. Allen, I. Bergqvist, R. E. Chrien, D. Gardner, W. P. Poenitz (contributing authors), Neutron Radiative Capture: Neutron Physics and Nuclear Data in Science and Technology, page 33,

     In the next step, the giant dipole state may deexcite by the emission of γ-rays. This reaction is called "semidirect". It turns out that direct and semidirect reactions play a dominating role at neutron energies higher than about 5 MeV.

   • 2003, Toshiki Naruse, Equalized & Synchronized Production: The High-Mix Manufacturing System that Moves Beyond JIT, page 8,

     In response to the supplier's request for improving the semidirect operations (parts supply and line management operations) at the final assembly processes and reducing labor requirements for semidirect operations, JMAC began its assessment of the situation by researching and analyzing in detail the current operations and work methods.

   • 2011, Multiple authors, Chapter 12: Atmospheric Composition Change: Climate-Chemistry Interactions, Ann Henderson-Sellers, Kendal McGuffie (editors), The Future of the World's Climate, page 341,

     The term semidirect aerosol effect was first introduced by Hansen, et al. (1997). […] This triggered a number of model studies investigating the semidirect aerosol effect on a global-scale.^[sic]

2. (mathematics, group theory) That has the nature of, or has a nature that derives from or is analogous to, a semidirect product.
   • 1971, Transactions of the Moscow Mathematical Society, page 261,

     It follows from 2° that σ induces the action homomorphism θ = σπ₁, which we call semidirect. We say that σ is a homomorphic transformation of (A, U).

     If θ is the semidirect action homomorphism, then it follows from 1° that the θ-module is the semidirect sum ^𝔇 of (A^×U^×) and (B, V).

   • 2002, Joseph J. Rotman, Advanced Modern Algebra, American Mathematical Society, Graduate Studies in Mathematics, Volume 114, 2nd Edition, page 761,

     A semidirect product is so called because a direct product G of K and Q requires, in addition to K + Q = G and K ∩ Q = {1}, that both subgroups K and Q be normal (Proposition 1.86); here, only one subgroup must be normal.

   • 2012, Arkadij L. Onishchik, Ernest B. Vinberg, Lie Groups and Algebraic Groups, page 37,

     Problem 37. A semidirect sum of Lie algebras is a Lie algebra.

Derived terms

• semidirect product
• semidirect sum