>> I need to know whether a repeating event occurs or not on a particular
>> day. I currently have the following information:
>>
>> date of first occurrence (date)
>> repeat frequency (interval)
>> date to check (date)
>>
>> My instinct says that I should be using a mod here to calculate whether
>> the remainder is zero when the difference between the two times is
>> divided by the repeat frequency. Unfortunately this is not possible
>> since as far as I am aware intervals only specify a time length and not
>> two dates.
> Huh? If you only need this good to day precision, as your reference to
> dates suggests, then just subtract the two dates (which will give an
> integer number of days) and modulo by the repeat frequency (also given
> as an integer number of days).
>
> If that doesn't satisfy your requirements, you need to be more clear
> about what they are.
Apologies for the lack of clarity.
Try repeat_frequency='1 month'
Netzach