| F. van Raamsdonk, P. Severi, M. H. Srensen, and H. Xi. Perpetual reductions in lambda calculus. Inf. and Comp., 149(2):173-225, 1999. 15 |
....( computes the normal form using the leftmost outermost strategy. This can be used to derive bounds for the length of reduction sequences that follow this strategy. Yet by only a minor tweak to the definition of ( it is possible to make the reduction strategy perpetual (in the sense of [vRSSX99]) so that the number of steps performed limits the height of the reduction tree altogether. To this end we slightly modify the grammar of #R (and its coinductive analogue) by adding a term as an index of the # constructor: # s r. The respective clause in the definition of ( is ....
....# n in subsection 3.3 to include reductions on the side term: r[s]#s # n t s #m s # 0 (#r)s#s # n m 1 t r[s]#s # n t 0 Herein, the free variables FV r are defined recursively as usual. The strategy # : # n is perpetual: it finds the longest possible reduction strategy (as reproved in [vRSSX99] with di#erent notations) 4.2. Types. Simple) Types #, #, # are generated from basic types # by # #. The level of # is given by lev # : 0 and lev (# #) max 1 lev #, lev # . The typed # calculi (in Church form) are obtained from the untyped ones by attaching types to # abstractions: ....
[Article contains additional citation context not shown here]
Femke van Raamsdonk, Paula Severi, Morten Heine Srensen, and Hongwei Xi. Perpetual reductions in lambda-calculus. Information and Computation, 149(2):173--225, 1999.
....= zt) xr)s) zt) r[x : s] t[z : r[x : s] ut 12 This result can be used to derive strong normalizability of terms in J from their strong normalizability as terms of . First, we recall a basic property of # , which has also been dubbed the fundamental lemma of perpetuality [vRSSX99]: Proposition 11. x 2 r = # ( xr)s) # (r[x : s] 1; x 62 r = # ( xr)s) # r # s 1: Lemma 12. r s = # r # s. Proof. Induction on . The inner reductions are all quite straightforward. The interesting case is that of a permutation In , the two ....
Femke van Raamsdonk, Paula Severi, Morten Heine Srensen, and Hongwei Xi. Perpetual reductions in lambda-calculus. Information and Computation, 149(2):173-225, 1999.
....( computes the normal form using the leftmost outermost strategy. This can be used to derive bounds for the length of reduction sequences that follow this strategy. Yet by only a minor tweak to the de nition of ( it is possible to make the reduction strategy perpetual (in the sense of [vRSSX99]) so that the number of steps performed limits the height of the reduction tree altogether. To this end we slightly modify the grammar of R (and its coinductive analogue) by adding a term as an index of the constructor: k j rs j r j Rr j s r: The respective clause in the de nition of ( ....
....3.3 to include reductions on the side term: r[s] s ; n t s ;m s 0 62 FV r ( r)s s ; n m 1 t r[s] s ; n t 0 2 FV r ( Herein, the free variables FV r are de ned recursively as usual. The strategy ; n ; n is perpetual: it nds the longest possible reduction strategy (as reproved in [vRSSX99] with di erent notations) 4.2. Types. Simple) Types ; are generated from basic types by . The level of is given by lev : 0 and lev ( maxf1 lev ; lev g. The typed calculi (in Church form) are obtained from the untyped ones by attaching types to abstractions: ....
[Article contains additional citation context not shown here]
Femke van Raamsdonk, Paula Severi, Morten Heine Srensen, and Hongwei Xi. Perpetual reductions in lambda-calculus. Information and Computation, 149(2):173-225, 1999.
No context found.
F. van Raamsdonk, P. Severi, M. H. Srensen, and H. Xi. Perpetual reductions in lambda calculus. Inf. and Comp., 149(2):173-225, 1999. 15
No context found.
Femke van Raamsdonk, Paula Severi, Morten Heine Srensen, and Hongwei Xi. Perpetual reductions in lambda calculus. Information and Computation, 149(2):173-225, March 1999. 10
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F. van Raamsdonk, P. Severi, M. H. Sorensen and H. Xi. Perpetual Reductions in Lambda Calculus. Information and Computation 149, pages 173-225, 1999.
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