(These tutorials include both java and flash. Both are supported by default in current browsers. You can return to this page at any point by clicking on the close button. You might, depending on how your browser is behaving, have to maximze the new window opened. (That is a button in the upper right hand corner.))

Each sentence of our system will be either an atomic sentence or a compound (or complex) sentences. Compound sentences will be either a conjunction, a disjunction, a conditional, a biconditional or a negation. Compound sentences are constructed from previous sentences as specified in the definition of "sentence of our language". Virtually everything we do will require that we recognize the structure of the sentences of our language. At this point you should view the initial walk-through on:

As you studied the distinction between those strings of symbols that are sentences and those that are not you perhaps noticed that each compound sentence has a main connective- the one that, in terms of the construction tree, was introduced last. Where this connective is '~' the sentence is a negation, where '&' a conjunction, where 'v' a disjunction, where '->' a conditional, and where '<->' a bicondtional. At this point you should view the second walk-through on: