1. On Sundays when a commemoration of vigil rank occurs or whenever two canons are appointed in the Menaion -- the Canon of the Cross and Resurrection is entirely omitted.
2. On Sundays when a commemoration of polyelos, doxology or six-stichera rank occurs and only one canon is appointed in the Menaion, two troparia are appointed from the Canon of the Cross and Resurrection. The theotokia/stavrotheotokia or triadica, if such occur, are omitted.
3. Whenever there is a simple commemoration on a Sunday, three troparia from the canon of the Cross and Resurrection are appointed. In such a case, the theotokia/stavrotheotokia and triadica, when they occur, are read/sung. In those instances where an ode has only two troparia, one of the troparia is repeated.
Any stavrotheotokion that might occur in a canon is always treated just as any other theotokion in a canon.
In the various Canons of the Cross and Resurrection (there is one for each of the eight tones), there is a fair amount of variety.
In some instances, an ode will have only two troparia without a theotokion/stavrotheotokion or triadicon.
Sometimes an ode will have two troparia together with a theotokion/stavrotheotokion, and sometimes an ode will have two troparia together with a triadicon.
By the way, the only Canon of the Cross and Resurrection that has stavrotheotokia is the one in Tone VI.
Edited, from a post by Daniel Olson daniel@kronstadt.orgto the USTAV list on Oct 24 2001 (ns)
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