Eckhard Bick - VISL

(4) Rule complexity
number of
contexts
morf syn map all
morf0 morf1 morf2 morf3 syn0 syn1 syn2 syn3
0 - - - - - - - - 39 39
1 172 77 16 44 54 8 12 14 57 54
2 317 70 14 14 159 26 15 - 127 742
3 383 62 8 8 219 41 3 - 170 894
4 249 73 2 2 214 46 3 - 187 776
5 143 51 10 2 204 47 4 - 150 611
6 81 29 2 2 173 42 - - 101 430
7 37 7 - - 115 29 2 - 71 262
8 23 5 - - 58 27 1 - 33 147
9 12 4 - - 39 12 4 - 23 94
10 4 4 - - 30 10 2 - 10 60
11 1 - - - 27 10 1 - 3 42
12 1 - - - 15 10 - - 2 28
13 1 - - - 23 7 - - 5 36
14 1 - - - 17 - - - 1 19
15 - 1 - - 11 1 - - - 13
16 - - - - 3 - - - - 3
17 1 - - - - - - - - 1
18 - - - - 1 - - - - 1
19 - - - - 1 - - - - 1
20 - - - - 1 - - - - 1
21 - - - - - - - - - -
22 - - - - 2 - - - - 2
23 - - - - 1 - - - - 1
all rules 1426 383 53 72 1367 316 47 14 979 4657
average per
rule
3.37 3.40 2.60 1.75 5.28 5.75 3.66 1.00 4.22 4.14
On average, 4 context conditions have to be true before a rule can be successfully
applied to its target. Syntactic rules are more complex (5.28 contexts for non-heuristic
rules), and morphological rules less complex (3.37 contexts for non-heuristic rules) than
the average. Mapping rules display an intermediate degree of complexity (4.22
contexts), on the one hand they apply to morphological targets, on the other they add
syntactic structure. Also, adding more context conditions is not the only way to make a
mapping rule more safe, a common alternative is to keep some ambiguity, map a longer
string of function tags, and leave disambiguation to the syntactic module proper.
Generally, there is less complexity on the higher heuristic levels, reflecting the
fact that these rules are less safe, incorporating fewer context conditions that would
limit the rule to less general - and thus safer - cases. Still, on the first heuristic level
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