Hiding property

Another consequence of Lemma 8.3 is that the result z gives no (Shannon) information about the first parameter, X, of exp x, X2), if X2 is chosen uniformly at random. This is called a hiding property, because the result z hides xj perfectly. 

Lemma 8.34. For families of hiding homomorphisms, the hiding property from Definition 8.31c can be replaced by the following shorter statement ... 

Proof. For each K e Good, the two parts of the hiding property must be shown. 

Proof. It has to be shown that Definitions 8.31a, b, d, 8.33a, and the simpler version of the hiding property that replaces Definition 8.31c for homomorphisms according to Lemma 8.34, are fulfilled. 

Optical. The optical properties of fillers and the influence that fillers have on the optical properties of filled systems are often misunderstood. The key parameters in understanding the optical properties of fillers themselves are filler psd, color, and index of refraction. These characteristics influence the optical properties of filled composition, such as color, brightness, opacity, hiding power, and gloss. 

The si2e of the vegetable tanning molecules and the coUoidal nature of the system result in the fixation in the hide of filling materials. The filling action is essentially an impregnation of the hide to form a dense firm leather. These properties are gready desired in sole and mechanical leathers. 

They may not provide superior hiding or coverage because these properties are not as important for primers as they are for topcoat paints. Primers may also contain specialty pigments and additives to help resist corrosion or prevent stain bleed-through. 

This proliferation in the use of color additives was soon recognized as a threat to the pubHc s health. Of particular concern were the practices of a dding poisonous colorants to food, and of using dyes to hide poor quaUty or to add weight or bulk to certain items. References 5—14 provide additional information on the history of food colorants and thek regulation. Reference 15 provides more information regarding the appHcations, properties, specifications, and analysis of color additives, as well as methods for the determination of colorants in products. 

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