Definition of "semidirect" in English

adjective

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.
   • 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.

2. (mathematics, group theory) That has the nature of, or has a nature that derives from or is analogous to, a semidirect product.

   • 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.