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Mirrors > Home > MPE Home > Th. List > df-plig | Structured version Visualization version Unicode version |
Description: Define the class of
planar incidence geometries. We use Hilbert's
axioms and adapt them to planar geometry. We use for the
incidence relation. We could have used a generic binary relation, but
using allows
us to reuse previous results. Much of what follows
is directly borrowed from Aitken, Incidence-Betweenness Geometry,
2008, http://public.csusm.edu/aitken_html/m410/betweenness.08.pdf.
The class is the class of planar incidence geometries, where a planar incidence geometry is defined as a set of lines satisfying three axioms. In the definition below, denotes a planar incidence geometry, so denotes the union of its lines, that is, the set of points in the plane, denotes a line, and denote points. Therefore, the axioms are: 1) for all pairs of (distinct) points, there exists a unique line containing them; 2) all lines contain at least two points; 3) there exist three non-collinear points. (Contributed by FL, 2-Aug-2009.) |
Ref | Expression |
---|---|
df-plig |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cplig 27326 | . 2 | |
2 | va | . . . . . . . . 9 | |
3 | 2 | cv 1482 | . . . . . . . 8 |
4 | vb | . . . . . . . . 9 | |
5 | 4 | cv 1482 | . . . . . . . 8 |
6 | 3, 5 | wne 2794 | . . . . . . 7 |
7 | vl | . . . . . . . . . 10 | |
8 | 2, 7 | wel 1991 | . . . . . . . . 9 |
9 | 4, 7 | wel 1991 | . . . . . . . . 9 |
10 | 8, 9 | wa 384 | . . . . . . . 8 |
11 | vx | . . . . . . . . 9 | |
12 | 11 | cv 1482 | . . . . . . . 8 |
13 | 10, 7, 12 | wreu 2914 | . . . . . . 7 |
14 | 6, 13 | wi 4 | . . . . . 6 |
15 | 12 | cuni 4436 | . . . . . 6 |
16 | 14, 4, 15 | wral 2912 | . . . . 5 |
17 | 16, 2, 15 | wral 2912 | . . . 4 |
18 | 6, 8, 9 | w3a 1037 | . . . . . . 7 |
19 | 18, 4, 15 | wrex 2913 | . . . . . 6 |
20 | 19, 2, 15 | wrex 2913 | . . . . 5 |
21 | 20, 7, 12 | wral 2912 | . . . 4 |
22 | vc | . . . . . . . . . . 11 | |
23 | 22, 7 | wel 1991 | . . . . . . . . . 10 |
24 | 8, 9, 23 | w3a 1037 | . . . . . . . . 9 |
25 | 24 | wn 3 | . . . . . . . 8 |
26 | 25, 7, 12 | wral 2912 | . . . . . . 7 |
27 | 26, 22, 15 | wrex 2913 | . . . . . 6 |
28 | 27, 4, 15 | wrex 2913 | . . . . 5 |
29 | 28, 2, 15 | wrex 2913 | . . . 4 |
30 | 17, 21, 29 | w3a 1037 | . . 3 |
31 | 30, 11 | cab 2608 | . 2 |
32 | 1, 31 | wceq 1483 | 1 |
Colors of variables: wff setvar class |
This definition is referenced by: isplig 27328 |
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