In algebraic geometry and algebraic topology, a branch of mathematics, A homotopy theory is a way to apply the techniques of algebraic topology, specifically homotopy, to algebraic varieties and, more generally, to schemes.
 The theory is due to Fabien Morel and Vladimir Voevodsky.
 The underlying idea is that it should be possible to develop a purely algebraic approach to homotopy theory by replacing the unit interval [0, 1] , which is not an algebraic variety, with the affine line A , which is.
 The theory requires a substantial amount of technique to set up, but has spectacular applications such as Voevodsky's construction of the derived category of mixed motives and the proof of the Milnor and Bloch-Kato conjectures.
From Here to Infinity: A Guide to Today's Mathematics, a 1996 book by mathematician and science popularizer Ian Stewart, is a guide to modern mathematics for the general reader.
 It aims to answer questions such as "What is mathematics?"
, "What is it for " and "What are mathematicians doing nowadays?"
.
 Author Simon Singh describes it as "An interesting and accessible account of current mathematical topics".
Fabien Morel is a French algebraic geometer and key developer of A¹ homotopy theory with Vladimir Voevodsky.
 Among his accomplishments is the proof of the Friedlander conjecture, and the proof of the complex case of the Milnor conjecture stated in Milnor's 1983 paper 'On the homology of Lie groups made discrete'.
 This result was presented at the Second Abel Conference, held in January–February 2012.
In mathematics and computational geometry, a Delaunay triangulation for a given set P of discrete points in a plane is a triangulation DT(P) such that no point in P is inside the circumcircle of any triangle in DT(P).
 Delaunay triangulations maximize the minimum angle of all the angles of the triangles in the triangulation; they tend to avoid sliver triangles.
 The triangulation is named after Boris Delaunay for his work on this topic from 1934.
Abraham Robinson (born Robinsohn; October 6, 1918 – April 11, 1974) was a mathematician who is most widely known for development of non-standard analysis, a mathematically rigorous system whereby infinitesimal and infinite numbers were reincorporated into modern mathematics.
 Nearly half of Robinson's papers were in applied mathematics rather than in pure mathematics.
In algebraic geometry, the "h" topology is a Grothendieck topology introduced by Vladimir Voevodsky to study the homology of schemes.
 It has several variants, such as the "qfh" and "cdh" topologies.
An abstract structure in mathematics is a formal object that is defined by a set of laws, properties, and relationships in a way that is logically if not always historically independent of the structure of contingent experiences, for example, those involving physical objects.
 Abstract structures are studied not only in logic and mathematics but in the fields that apply them, as computer science, and in the studies that reflect on them, such as philosophy and especially the philosophy of mathematics.
 Indeed, modern mathematics has been defined in a very general sense as the study of abstract structures (by the Bourbaki group: see discussion there, at algebraic structure and also structure).
Vladimir Alexandrovich Voevodsky ( ; Russian: Влади́мир Алекса́ндрович Воево́дский , 4 June 1966 - 30 September 2017) was a Russian mathematician.
 His work in developing a homotopy theory for algebraic varieties and formulating motivic cohomology led to the award of a Fields Medal in 2002.
 He is also known for the proof of the Milnor conjecture and motivic Bloch-Kato conjectures and for the univalent foundations of mathematics and homotopy type theory.
Boris Nikolaevich Delaunay or Delone (Russian: Бори́с Никола́евич Делоне́ ; March 15, 1890 – July 17, 1980) was one of the first Russian mountain climbers and a Soviet/Russian mathematician, and the father of physicist Nikolai Borisovich Delone.
In mathematics, the norm residue isomorphism theorem is a long-sought result relating Milnor "K"-theory and Galois cohomology.
 The result has a relatively elementary formulation and at the same time represents the key juncture in the proofs of many seemingly unrelated theorems from abstract algebra, theory of quadratic forms, algebraic K-theory and the theory of motives.
 The theorem asserts that a certain statement holds true for any prime formula_1 and any natural number formula_2.
 John Milnor speculated that this theorem might be true for formula_3 and all formula_2, and this question became known as Milnor's conjecture.
 The general case was conjectured by Spencer Bloch and Kazuya Kato and became known as the Bloch–Kato conjecture or the motivic Bloch–Kato conjecture to distinguish it from the Bloch–Kato conjecture on values of "L"-functions.
 The norm residue isomorphism theorem was proved by Vladimir Voevodsky using a number of highly innovative results of Markus Rost.

Question: Which Russian Mathematician would have studied modern mathematics, Boris Delaunay or Vladimir Voevodsky?
Answer: Vladimir Alexandrovich Voevodsky ( ; Russian: Влади́мир Алекса́ндрович Воево́дский , 4 June 1966 - 30 September 2017)