Implementation of mathematics in set theory: Difference between revisions

Revision as of 03:05, 21 December 2005

Revision as of 03:06, 21 December 2005

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The <strong>field</strong> of a relation R is the union of the ___domain and range of R.

The <strong>preimage</strong> of an element x of the field of R is the set <math>\{y \mid y R xRx\}</math> (used in the definition of "well-founded" below).

The <strong>relative product</strong> <math>R|S</math> is the relation <math>\{(x,z) \mid (\exists y.x R y \wedge y S z)\}</math>.