Implicit, virtual, constructive mean being such by correct or justifiable inference rather than by direct statement or proof.
Something is implicit (as opposed to explicit ) which is implied (as by the words, acts, appearance, character, or methods of the person or thing concerned) but is not definitely stated or expressed.
Something is virtual (as opposed to actual ) which exists in essence or effect but is not actually designated or recognized or put forward or regarded as such.
Something is constructive (as opposed to manifest ) which is inferred from a text, from known acts, or known conditions and which rests therefore on an interpretation of this text, these acts, or these conditions rather than upon direct statement or direct evidence.