Explain what it means for a sentence $A$ to be a logical consequence of a set of sentences $\{{}_1,$dots,${}_n\}.$ Using your definition of logical consequence, explain what it means for an argument with the following structure to count as a valid argument. $(4$ marks$)$

Indicate which of the following strings of symbols count as sentences in the language of truth functional logic we are working with in class. $(6$ points$)$

notPvv$Qharrnot{P}^{{?}^{?}}Q$

$[(PQ{)}^{{?}^{?}}Q]$longrightarrow

$-()({}^{{?}^{?}})$

${}_1,$dots,${}_n+A$

$1$

$-$SVT