"valid and/or satisfiable"

[Roman]

Can a formula be both valid and satisfiable? It makes sense by
definitions, but can it be called both?

Thanks.

[Omer Beg]

Post by Roman
Can a formula be both valid and satisfiable?
It makes sense by definitions,
but can it be called both?

Yes. A formula which is valid is always satisfiable.
But a satisfiable forumla may or may not be valid.