Why there is no mention of conjunction in the Avicennian system of logic?

In the Avicennian system of logic, the types of propositions are exclusive to categorical propositions, conjunctive conditional propositions, and disjunctive conditional propositions. So, this important question arises: Why Avicennian logicians have not addressed conjunctions? Our attempt in the current research is, to provide an acceptable answer to the question. In the Avicennian logic, the criterion for a sentence being a proposition is that by saying it, a single judgment is expressed by the speaker. According to the criterion, categorical and conditional propositions are considered to be types of proposition because expressing them implies only a single judgment. As a result, conjunctive propositions cannot be placed as a type of propositions, next to categorical and conditional propositions; because unlike the parts of conditional sentences, which do not have truth value, expressing a conjunctive proposition implies several judgment, and its parts have truth value during the combination.