Uffe Flarup Hansen, Klaus Meer. Two logical hierarchies of optimization problems over the real numbers. Math. Log. Q., 52(1):37-50, 2006. [doi]
@article{HansenM06:0,
title = {Two logical hierarchies of optimization problems over the real numbers},
author = {Uffe Flarup Hansen and Klaus Meer},
year = {2006},
doi = {10.1002/malq.200510021},
url = {http://dx.doi.org/10.1002/malq.200510021},
tags = {optimization},
researchr = {https://researchr.org/publication/HansenM06%3A0},
cites = {0},
citedby = {0},
journal = {Math. Log. Q.},
volume = {52},
number = {1},
pages = {37-50},
}