| Some definitions of interest. |
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append | Def as @ bs == Case of as; nil bs ; a.as' [a / (as' @ bs)] (recursive) |
| | Thm* T:Type, as,bs:T List. (as @ bs) T List |
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firstn | Def firstn(n;as)
Def == Case of as
Def == Canil nil
Def == Caa.as' if 0< n [a / firstn(n-1;as')] else nil fi
Def (recursive) |
| | Thm* A:Type, as:A List, n: . firstn(n;as) A List |
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int_iseg | Def {i...j} == {k: | i k & k j } |
| | Thm* i,j: . {i...j} Type |
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length | Def ||as|| == Case of as; nil 0 ; a.as' ||as'||+1 (recursive) |
| | Thm* A:Type, l:A List. ||l||  |
| | Thm* ||nil||  |
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nth_tl | Def nth_tl(n;as) == if n 0 as else nth_tl(n-1;tl(as)) fi (recursive) |
| | Thm* A:Type, as:A List, i: . nth_tl(i;as) A List |