Editing Intuitionistic logic (section)

====Functionally complete connectives====
As shown by [[Alexander Kuznetsov (mathematician)|Alexander V. Kuznetsov]], either of the following connectives – the first one ternary, the second one quinary – is by itself [[functionally complete]]: either one can serve the role of a sole sufficient operator for intuitionistic propositional logic, thus forming an analog of the [[Sheffer stroke]] from classical propositional logic:{{sfn|Chagrov|Zakharyaschev|1997|pages=58-59}}
* <math>\big((P\lor Q)\land\neg R\big)\lor\big(\neg P\land(Q\leftrightarrow R)\big)</math>
* <math>P\to\big(Q\land\neg R\land(S\lor T)\big)</math>