This document discusses key concepts related to meaning at the sentence level, including:
1) The difference between an utterance and a sentence, with an utterance being a stretch of talk by a speaker and a sentence being a string of words put together by grammatical rules.
2) Propositions, which are the condition that would make a sentence true.
3) Sentence relations like synonymy, entailment, contradiction, and presupposition which relate to how the meaning and truth value of one sentence depends on another.
4) Logical concepts used to determine truth value and truth conditions of sentences like negation, conjunction, disjunction, modus ponens, and modus toll