The unbounded μ-operator is defined by Minsky (1967) p. 210 but with a peculiar flaw: the-operator will not yield "t"=0 when its predicate (the IF-THEN-ELSE test) is satisfied; rather it yields "t"=2. In Minsky's version the counter is ""t"", and the function φ("t", x) deposits its number in register φ. In the usual μ definition register "w" will contain 0, but Minsky observes that it can contain any number "k". Minsky's instruction set is equivalent to the following where "JNE" = Jump to z if Not Equal: