@Override
	public byte[] toConcrete(Pair<L, R> value, Purpose purpose) {
		return leftArith.toConcrete(value.getLeft(), purpose);
	}
Construct a composed arithmetic from the given two

@param leftArith the left ("control") arithmetic
@param rightArith the right ("rider") arithmetic
Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/exec/PairedPcodeArithmetic.java