What is a valid formula in logic?

A formula is valid iff it is true for all models and all variable assignments.

Or, a formula is valid iff it is true in all structures(structure=model, which is a pair(D,J) where D is a discourse and J is a mapping) and all variable assignments.

The following sentences are equivalent.

A formula is valid.

A formula is logically valid.

A formula is universally valid.

A formula is logically true.

A formula is logical truth.

A formula is a tautology.

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