Harald Hempel, Gerd Wechsung. The Operators min and max on the Polynomial Hierarchy. Electronic Colloquium on Computational Complexity (ECCC), 4(25), 1997. [doi]
@article{ECCC-TR97-025,
title = {The Operators min and max on the Polynomial Hierarchy},
author = {Harald Hempel and Gerd Wechsung},
year = {1997},
url = {http://eccc.hpi-web.de/eccc-reports/1997/TR97-025/index.html},
researchr = {https://researchr.org/publication/ECCC-TR97-025},
cites = {0},
citedby = {0},
journal = {Electronic Colloquium on Computational Complexity (ECCC)},
volume = {4},
number = {25},
}