；完满拉丁方；完满正方形- fork graph
- forking
- form
- formal
- formal adjoint
- formal adjoint operator
- formal algebraic space
- formal argument
- formal arithmetic
- formal axiomatics
- formal axiomatic theory
- formal Bayes estimate
- formal Bayes estimator
- formal calculus
- formal category
- formal completion
- formal complex
- formal complex space
- formal computation
- formal consistent system
- formal contradictory system
- formal definition
- formal deformation
- formal degree
- formal derivation