Editing First-order logic (section)

===Fixpoint logic===
{{main|Fixed-point logic}}
Fixpoint logic extends first-order logic by adding the closure under the least fixed points of positive operators.<ref>{{cite book | title=Computer Science Logic: 6th Workshop, CSL'92, San Miniato, Italy, September 28 - October 2, 1992. Selected Papers | volume=702 | series=Lecture Notes in Computer Science | editor1-first=Egon | editor1-last=Börger | publisher=[[Springer-Verlag]] | year=1993 | zbl=0808.03024 | isbn=3-540-56992-8 | pages=100–114 | first=Uwe | last=Bosse | chapter=An Ehrenfeucht–Fraïssé game for fixpoint logic and stratified fixpoint logic }}</ref>