 (where the subscripts are added to distinguish the two definitions), then we can see that \(\textsf{Y}_1 M=M(\textsf{Y}_1M)\), but for \(\textsf{Y}_2\), \(\textsf{Y}_2M\triangleright M(\textsf{Y}_2M)\) holds too. In this respect, \(\textsf{Y}_1\) is similar to Curry’s fixed point combinator (and really, to any fixed point combinator), whereas \(\textsf{Y}_2\) is like Turing’s fixed point combinator.