# 星之一角

What have you found for these years?

## 2010-02-21

### domain theory

Semantics of Functional Programming Languages,

because some functions (for example, the successor
function) do not have a fixed point. At best, the
genuine function corresponding to Y would have to be a
partial function, necessarily undefined at some inputs.
[...]
an additional element that represents an undefined
output, i.e. the "result" of a computation that never ends.

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