Recently, the Department of Mathematics at
our University issued a recommendation encouraging its members
to publish their research in non-specialized, mainstream mathematical journals. For
numerical analysts this will make an additional obstacle for their promotions. But even
for discrete mathematicians this recommendation is causing concerns. 


For several top mainstream journals I checked with tools offered by MathSciNet what percentage
of discrete mathematical papers they published in recent years. Some statistics indicate that in some journals the number of papers with primary MSC classification, say 05 or 06 decreased significantly in the past 30 years. There are several possible explanations to this fact. 


* The quality of research in DM is dropping.
* The majority of research in discrete mathematics is so specialized that it is of no interest for the rest of mathematics
* Some discrete mathematics journals attract even the best work of discrete mathematicians.
* Some top journals may be biased against discrete math.
* Maybe discrete math is no longer part of mainstream mathematics and will, like theoretical computer science, eventually develop into an independent body of research.


But the key issue is whether discrete math is nowadays perceived as mainstream mathematics. 



Is discrete mathematics mainstream?
There are two different questions here, one objective and one subjective. I will try to give my view, for what it's worth. Bear with me.


First, you are asking what is the publication history of discrete mathematics? (Even if I suspect you know this much better than I do.) Well, originally there was no such thing as DM. If I understand the history correctly, classical papers like [A logical expansion in mathematics](https://projecteuclid.org/journals/bulletin-of-the-american-mathematical-society-new-series/volume-38/issue-8/A-logical-expansion-in-mathematics/bams/1183496087.full) by Hassler Whitney (on coefficients of chromatic polynomials) were viewed as contributions to "mainstream mathematics". What happened is that starting maybe late 60s there was a rapid growth in the number of papers in mathematics in general, with an even greater growth in discrete mathematics. While the overall growth is relatively easy to explain as a consequence of expansion of graduate programs, the latter is more complicated. Some would argue that CS and other applications spurned the growth, while others would argue that this area was neglected for generations and had many easy pickings, inherent in the nature of the field. Yet others would argue that the growth is a consequence of pioneer works by the "founding fathers", such as Paul Erdős, Don Knuth, G.-C. Rota, M.-P. Schützenberger, and W.T. Tutte, which transformed the field. Whatever the reason, the "mainstream mathematics" felt a bit under siege by numerous new papers, and quickly closed ranks. The result was a dozen new leading journals covering various subfields of combinatorics, graph theory, etc., and few dozen minor ones. Compare this with the number of journals dedicated solely to algebraic geometry to see the difference. Thus, psychologically, it is very easy to explain why journals like *Inventiones* even now have relatively few DM papers - if the DM papers move in, the "mainstream papers" often have nowhere else to go. Personally, I think this is all for the best, and totally fair.


Now, your second question is whether DM is a "mainstream mathematics", or what is it? This is much more difficult to answer since just about everyone has their own take. E.g. **miwalin** suggests above that number theory is a part of DM, a once prevalent view, but which is probably contrary to the modern consensus in the field. Still, with the growth of "arithmetic combinatorics", part of number theory is definitely a part of DM. While most people would posit that DM is "combinatorics, graph theory + CS and other applications", what exactly are these is more difficult to decide. The split of *Journal of Combinatorial Theory* into Series A and B happened over this kind of disagreement between Rota and Tutte (still legendary). I suggest [combinatorics wikipedia page](https://en.wikipedia.org/wiki/Combinatorics) for a first approximation of the modern consensus, but when it comes to more concrete questions this becomes a contentious issue sometimes of "practical importance". As an editor of *[Discrete Mathematics](https://en.wikipedia.org/wiki/Discrete_Mathematics_(journal))*, I am routinely forced to decide whether submissions are in scope or not. For example if someone submits a generalization of [R–R identities](https://en.wikipedia.org/wiki/Rogers-Ramanujan_identities) — is that a DM or not? (If you think it is, are you sure you can say what exactly is "discrete" about them?) Or, e.g. is Cauchy theorem a part of DM, or metric geometry, or both? (or neither?) How about "IP = PSPACE" theorem? Is that DM, or logic, or perhaps lies completely outside of mathematics? Anyway, my (obvious) point is that there is no real boundary between the fields. There is a large spectrum of papers in DM which fall somewhere in between "mainstream mathematics" and applications. And that's another reason to have separate "specialized" journals to accommodate these papers, rather than encroach onto journals pre-existing these new subfields. Your department's "encouragement" to use only the "mainstream mathematical journals" for promotion purposes is narrow minded and very unfortunate.


