EDB — 00G

[00G] (Solved on 2022-10-11) Well-formed formulas are

• atomic formulas, i.e. composed of a single variable, or

• a formula of the type $\neg (𝛼)$ where $𝛼$ is a well-formed formula, or

• • a formula of the type $(𝛼)\Rightarrow (𝛽)$ , or

  • a formula of the type $(𝛼)\iff (𝛽)$ , or

  • a formula of the type $(𝛼)\vee (𝛽)$ , or

  • a formula of the type $(𝛼)\wedge (𝛽)$ ,

  where $𝛼,𝛽$ are two well-formed formulas.