@SpookyKitty Does every word, as in use, not as in consideration, enlist a concept in its success at meaning in the word? Do prepositions in use have an enlisted concept satisfying your criteria for a concept? For example, can you work through how each of your conditions are satisfied for the preposition “of”? Rand tried to outline how prepositions fall within her theory of concepts. But she took them all to be as fundamentally operations of the mind, which I think false in the case of conjunction.
Does your group of criteria on concepts entail that they all can stand in hierarchical taxonomic relations? Or anyway, is your group compatible with that taxonomy circumstance?
When I think of the topic of concepts in recent decades, the names coming to mind are Christopher Peacocke’s A Study of Concepts and Jesse Prinz’s Furnishing the Mind. You might like to see how what you have distilled fits with what they got. Also, Meir Buzaglo’s The Logic of Concept Expansion and, concerning the developmental psychology of concepts and smoothness with your formula, Susan Carey’s The Origin of Concepts.*