Non-terminal symbol `Formulas_opt`

Defining rules for nonterminal symbol Formulas_opt:

`Formulas_opt`
		`Formulas`

Occurrences of symbol Formulas_opt in body of other rules:

`Formula`		`AND` `OPENPAR` `Formulas_opt` `CLOSEPAR`
`Formula`		`OR` `OPENPAR` `Formulas_opt` `CLOSEPAR`

Non-terminal symbol Formulas_opt