| FailureReason | Otter.SearchRes, Otter, Zsyntax |
| filterImpl | Zsyntax.Labelled.Rule.Frontier, Zsyntax.Labelled.Rule |
| filterUnsubsumed | Otter.Internal.Search |
| FKind | Zsyntax.Labelled.Formula |
| foc | Zsyntax.Labelled.Rule.Frontier, Zsyntax.Labelled.Rule |
| FocMatchRes | Zsyntax.Labelled.Rule.BipoleRelation, Zsyntax.Labelled.Rule |
| focus | Zsyntax.Labelled.Rule.BipoleRelation, Zsyntax.Labelled.Rule |
| foldActives | Otter.Internal.Structures |
| Formula | |
| 1 (Type/Class) | Zsyntax.Formula, Zsyntax |
| 2 (Data Constructor) | Zsyntax.Formula, Zsyntax |
| frmlHetEq | Zsyntax.Labelled.Formula |
| frmlHetOrd | Zsyntax.Labelled.Formula |
| frNeg | Zsyntax.Labelled.Rule.Frontier, Zsyntax.Labelled.Rule |
| fromCSCtxts | Zsyntax.ReactionList |
| frontier | Zsyntax.Labelled.Rule.Frontier, Zsyntax.Labelled.Rule |
| frPos | Zsyntax.Labelled.Rule.Frontier, Zsyntax.Labelled.Rule |
| FSChecked | Otter.Internal.Structures |
| FSCheckedNode | Otter.Internal.Structures |
| FullXiEmptyResult | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule |
| FullZetaXi | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule |
| fwdSubsumes | Otter.Internal.Structures |