Projective Geometry from a historical perspective Ambjrn Naeve

Projective Geometry from a historical perspective Ambjörn Naeve KMR (Knowledge Management Research group) CID (Centrum för användarorienterad IT Design) NADA (Institutionen för Numerisk Analys och Datalogi) KTH (Kungliga Tekniska Högskolan) e-mail: amb@nada. kth. se webb: http: //kmr. nada. kth. se

Alberti’s construction

Complete quadrangle - 1

Complete quadrangle - 2

Complete quadrilateral - 1

Complete quadrilateral - 2

Elliptisk involution

Hyperbolisk involution

Projectified cartesian coord. syst. in 2 dim

Projectified cartesian coords in 2 dim

Unit-point - unit-line in P 2

Involution-1. 1.

Involution-1. 2.

Involution-1. 3.

Involution-2. 1.

Involution-2. 2.

Involution-3. 1.

Moebius-angle-cross-ratio-1

Moebius-angle-cross-ratio-2

Moebius-net

Pascal’s theorem from Steiner’s theorem-1

Pascal’s theorem from Steiner’s theorem-2

Projective coordiates - 1

Projective coordiates - 2

Projective coordiates - 3

Projective coordiates - 4

Seydewitz sats - 1

Seydewitz sats - 2

Seydewitz sats - 3&4

Självpolär Diagonaltriangel - 1

Självpolär Diagonaltriangel - 2

Steiner’s sats - 1

Steiner’s sats - 2

Steiner’s sats - 3&4

Steiner’s sats -5

Polaritet inducerar involution - 1

Polaritet inducerar involution - 2

Polaritet inducerar involution - 3