Not exactly.

Assuming RM is a reference to Codd's seminal work ("A Relational Model
of Data for Large Data Banks", 1970), you need only look at the papers
he cited to find an earlier paper that showed the relationship between
mathematics and database management.

David L. Childs taught mathematics at the University of Michigan and
Codd cited his work. Here's the abstract for a March 1968 paper by
Childs:

DESCRIPTION OF A SET-THEORETIC DATA STRUCTURE
A set-theoretic data structure (STDS) is virtually a 'floating' or
pointer-free structure allowing quicker access, less storage, and
greater flexibility than fixed or rigid structures that rely heavily on
internal pointers or hash-coding, such as 'associative or relational
structures,' 'list structures,' 'ring structures,' etc. An STDS relies
on set-theoretic operations to do the work usually allocated to internal
pointers. A question in an STDS will be a set-theoretic expression. Each
set in an STDS is completely independent of every other set, allowing
modification of any set without perturbation of the rest of the
structure; while fixed structures resist creation, destruction, or
changes in data. An STDS is essentially a meta-structure, allowing a
question to 'dictate' the structure or data-flow. A question establishes
which sets are to be accessed and which operations are to be performed
within and between these sets. In an STDS there are as many 'structures'
as there are combinations of set-theoretic operations; and the addition,
deletion, or change of data has no effect on set-theoretic operations,
hence no effect on the 'dictated structures.' Thus in a floating
structure like an STDS the question directs the structure, instead of
being subservient to it.

And there's also ARPA-funded research described in this August 1968
research paper presented to the IFIP Congress 1968. Note the
INTRODUCTION below.

"Childs, D. L., Feasibility of a Set-Theoretic Data Structure: A General
Structure Based on a Reconstituted Definition of Relation"

ABSTRACT This paper is motivated by an assumption that many problems
dealing with arbitrarily related data can be expedited on a digital
computer by a storage structure which allows rapid execution of
operations within and between sets of datum names. In order for such a
structure to be feasible, two problems must be considered: 1. the
structure should be general enough that the sets involved may be
unrestricted, thus allowing sets of sets of sets...; sets of ordered
pairs, ordered triples...; sets of variable length n-tuples, n-tuples of
arbitrary sets; etc.; 2. the set-operations should be general in nature,
allowing any of the usual set theory operations between sets as
described above, with the assurance that these operations will be
executed rapidly. A sufficient condition for the latter is the existence
of a well-ordering relation on the union of the participating sets.
These problems are resolved in this paper with the introduction of the
concept of a 'complex,' which has an additional feature of allowing a
natural extension of properties of binary relations to properties of
general relations.

TABLE OF CONTENTS Page
ABSTRACT............................................ I.
INTRODUCTION..................................
II. COMPLEXES.................................... 5
III. EXTENSION OF SET OPERATIONS TO COMPLEXES...... 9
IV. ORDERED PAIR DEFINED BY A COMPLEX............. 11
V. FUNCTIONS..................................... 13
VI. DEVELOPMENT OF AN N-TUPLE..................... 14
VII. RECONSTITUTED DEFINITION OF RELATION.......... 18
VIII. TAU-ORDERING............................ 21
IX. EXTENDED OPERATIONS FOR RELATIONS............. 28
X. EXAMPLES.................................. 31
XI. CONCLUSION............................... 33
DEFINED SYMBOLS..................................... 35
REFERENCES.......................................... 37
vii

I. INTRODUCTION The overall goal, of which this paper is a part, is the
development of a machine-independent data structure allowing rapid
processing of data related by arbitrary assignment such as: the contents
of a telephone book, library files, census reports, family lineage,
networks, etc. Data which are non-intrinsically related have to be
expressed (stored) in such a way as to define the way in which they are
related before any data structure is applicable. Since any relation can
be expressed in set theory as a set of ordered pairs and since set
theory provides a wealth of operations for dealing with relations, a
set-theoretic data structure appears worth investigation.