Secure diffuse computing: class #6

Teacher: Serpette

# Hop semantics

- Slides
- Paper written by Serrano
- Wikipedia articles that might shed some light:

## $\beta$-equations

(1)\begin{align} \lambda x. M\;N\rightarrow M \{x/N\} \end{align}

(2)
\begin{equation} M[x:=N] \end{equation}

## Recursion

(3)\begin{align} (\lambda x.x\;x) = \Delta \end{align}

What means *apply x to itself*. This introduces a funny concept of x:

\begin{align} x \equiv x \rightarrow x \end{align}

(x is a set, marked as E on whiteboard by the teacher)

## Reductions

- Strong - reduction in compile time (ASAP)
- Weak
- Lazy/by need - (only Haskell?) passing unreduced results, reducing them only when needed
- ?/by value- (Lisp, Scheme) reduction when computing the function

In strong the strings are reduced before we know that we ever need them.

page revision: 16, last edited: 01 Dec 2009 10:33