LANTERN TRANSPARENCIES

A lantern lemma

We show that in the mapping class group of a surface any relation between Dehn twists of the form T j xT k y = M (M a multitwist) is the lantern relation, and any relation of the form (TxTy) k = M (where Tx commutes with M ) is the 2-chain relation. AMS Classification 57M07; 20F38, 57N05

[Use of transparencies to read patch tests].

Linear and nonlinear transparencies in binocular vision.

When the product of a vertical square-wave grating (contrast envelope) and a horizontal sinusoidal grating (carrier) are viewed binocularly with different disparity cues they can be perceived transparently at different depths. We found, however, that the transparency was asymmetric; it only occurred when the envelope was perceived to be the overlaying surface. When the same two signals were add...

Accuracy of color scission for spectral transparencies.

When surfaces are overlaid by a transparent filter, color scission refers to the perceptual separation of the colors of the image into the colors of the underlying surface and the color of the overlaying layer. We used filter matching to measure the accuracy of color scission for simulated physical filters and materials. Standard filters were placed on various sets of chromatic materials and ma...

Applications of the Lantern Identity

The purpose of this note is to unify the role of the lantern identity in the proof of several finiteness theorems. In particular, we show that for every nonnegative integer m, the vector space (over the rationals) of type m (resp. T -type m) invariants of integral homology 3-spheres are finite dimensional. These results have already been obtained by [Oh] and [GL2] respectively; our derivation h...