I am writing a piece of software that translates programs into programs (a "compiler", in informatics lingo) and my source language allows the programmer to specify Latin numerals.

In case the numeral is incorrect (e.g., IVI) or is too large (that is, above a predefined limit, here the largest is currently 999), I would like to print out error messages in English and Latin.

What would you recommend for the Latin (I need two messages, one for each error above)?

  • 3
    Shouldn't your IVI bad number actually convert to NaN (not a number) ??
    – ivanivan
    Commented Dec 13, 2018 at 18:55
  • 3
    NaN is a floating-point number such that it does not equal to itself, for example it is the result of a division by zero. These properties do not fit the context (natural numbers, where, for instance, the division by zero triggers an error) and IVI should perhaps more properly be described as an ill-formed number. In other words, being NaN is a property of a value, that is, a denotation, but my concern here is about the notation (being wrong). Commented Dec 13, 2018 at 21:35
  • Roman numeral system being additive (and non commutative), instead of positional (like the decimal system), an error here means an invalid addition (e.g., n + IV is valid, but not IV + n). Of course, the property for Roman numerals to be well-defined can be described by a context-free grammar (which I did), without the need to perform the additions. Commented Dec 13, 2018 at 21:53
  • Where is this language and how can I get it??? :)
    – bishop
    Commented Dec 14, 2018 at 2:22
  • The programming language is the next release of Michelson, the language for writing smart contracts on the Tezos blockchain. The macro instruction DIP { code } means that the piece of code is to be applied to the stack without a prefix of length one. For a prefix of length 3, you write DIIIP { code } and the next release will allow DXVIIP :) Commented Dec 14, 2018 at 9:59

2 Answers 2


I suggest numerus pravus for 'incorrect' and numerus nimius for 'too large'.


I would suggest:

In case the numeral is incorrect (e.g., IVI)

numerus falsus

... or is too large

numerus magnus nimis

Perhaps you can also add error: or erratum: at the beginning of the message (albeit the latter is commonly found in printed books for correcting printer errors, so not sure it fits in the context).


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