Instruction sequence notations with probabilistic instructions

This paper concerns probabilistic instruction sequences. We use the term probabilistic instruction sequence for an instruction sequence that contains probabilistic instructions, i.e. instructions that are themselves probabilistic by nature, rather than an instruction sequence of which the instructions are intended to be processed in a probabilistic way. We propose several kinds of probabilistic instructions, provide an informal operational meaning for each of them, and discuss related work. On purpose, we refrain from providing an ad hoc formal meaning for the proposed kinds of instructions.