@ernst, on some other forum, someone had posted about the "and/or" confusion in yoga rules. Oftentimes, a rule or yoga is not clear - are all planets in a list meant (and), or any planet in a list (or)?
One example: Medium life yogas, video "Using short medium and long life yogas" at 16:30 in the video:
Malefics in 2nd, 3rd, 4th, 5th, 8th and 11th.
In the video, you say that there are malefic Su/Ma in the 8th and Shani in 2nd, so the yoga is satisfied. So I guess what this rule really says is Malefics in 2nd, 3rd, 4th, 5th, 8th or 11th.
Also, I guess it means 1 or more malefics.
In the present example, there can be no ambiguity that 'and' really means 'or', because there are not 6 malefics in all in astrology. But in other cases I have seen, the rule becomes truly ambiguous.
How do we prevent such ambiguities from creeping in?
