* \isabellestyle{it} produces near math mode output;
* settings: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, XSYMBOL_HOME;
consts fib :: nat => nat
recdef fib "measure(%n. n)"
"fib 0 = 0"
"fib 1 = 1"
"fib (Suc(Suc x)) = fib x + fib (Suc x)"