In the Wikipedia article on Fixed-point combinator in the Values and domains section, we find the following:

$$x^2 = -1 \implies x = \frac{-1}x \implies fx = \frac{-1}x \bigwedge Yf = x$$

What does the $\bigwedge$ mean? How does $x = \frac{-1}x$ imply $fx = \frac{-1}x \bigwedge Yf = x$? My best guess is observing that $\lambda be.eb = \overline{b^e}$, then guessing that $\bigwedge$ means exponentiation, but that would still not explain why $fx = x$ or $\frac{-1}x \bigwedge Yf = x$.

  • 3
    $\begingroup$ This is most probably '$\land$', the logical 'and' connective. $\endgroup$
    – Berci
    Dec 10, 2021 at 15:47
  • $\begingroup$ Thanks. I'm still confused by $\frac{-1}x \wedge Yf$ in this context. $\endgroup$
    – joseville
    Dec 10, 2021 at 16:27
  • 2
    $\begingroup$ Yes, it is conjunction (logical and): $\land$. It reads: $fx=\frac {−1}{x} \text { and } \text {Y}f=x$ $\endgroup$ Dec 10, 2021 at 16:36

1 Answer 1


Examining the source code of the Wikipedia page indicates that this symbol is generated by \land, which denotes "logical and", or conjunction. Note the difference in size and weight between $\bigwedge$ and $\land$.


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