olemus
formaalloogika haru,
kasutab modaalsust väljendavaid operaatoreid,
laiendab klassikalist lause- ja predikaatarvutust
modaaloperaatorite ehk modaalsustega

ülevaateid
https://plato.stanford.edu/entries/logic-modal/

http://www.iep.utm.edu/modal-lo/

http://web.cecs.pdx.edu/~mperkows/PERKOWSKI_PRESENTATIONS/Perkowski.Seminar.SySc.2011.pdf

http://blog.sciencenet.cn/home.php?mod=attachment&id=34637

http://flolac.iis.sinica.edu.tw/flolac09/lib/exe/modal_logic.pdf

turvarakendusi
https://pdfs.semanticscholar.org/84ca/1d408330cd3fbb24bfa6c8206cea54933d33.pdf

http://crpit.com/confpapers/CRPITV38Liu.pdf

http://www.di.unito.it/~guido/alfieri/aucher-elal10b.pdf

http://dl.ifip.org/db/conf/forte/forte2007/Chae07.pdf

http://ieee-ims.org/ims/sas/2008/presentations/thursday/Session%20R1/R1Four.pdf

https://people.mpi-sws.org/~dg/papers/stm11-aclnew.pdf

https://eprint.iacr.org/2006/262.pdf