We recall a group-theoretic description of the first non-vanishing homotopy group of a certain (n+1)-ad of spaces and show how it yields several formulae for homotopy and homology groups of specific spaces. In particular we obtain an alternative proof of J. Wu’s group-theoretic description of the homotopy groups of a 2-sphere.

A b str act . Let Σ be the image of a topological embedding of Sn−2 into Sn. In this paper the homotopy groups of the complement Sn−Σ are studied. In contrast with the situation in the smooth and piecewise linear categories, it is shown that the first nonstandard homotopy group of the complement of such a topological knot can occur in any dimension in the range 1 through n − 2. If the first non...

The concept of the homotopy theory of modules was discovered by Peter Hilton as a result of his trip in 1955 to Warsaw, Poland, to work with Karol Borsuk, and to Zurich, Switzerland, to work with Beno Eckmann. The idea was to produce an analog of homotopy theory in topology. Yet, unlike homotopy theory in topology, there are two homotopy theories of modules, the injective theory, πn(A,B), and t...

In this work, we have applied Elzaki transform and He's homotopy perturbation method to solvepartial dierential equation (PDEs) with time-fractional derivative. With help He's homotopy per-turbation, we can handle the nonlinear terms. Further, we have applied this suggested He's homotopyperturbation method in order to reformulate initial value problem. Some illustrative examples aregiven in ord...

space is said to be rational if its homotopy groups are rational vector spaces. Quillen has shown that up to homotopy there is a one-one correspondence between rational spaces and differential graded Lie algebras over 0. Call a two-connected space tame if the divisibility of its homotopy groups increases with dimension just quickly enough to prevent stable k-invariants from appearing. We will s...

We show that the homotopy category of simplicial diagrams I-SS indexed by a small category I is equivalent to a homotopy category of SS ↓ NI simplicial sets over the nerve NI. Then their equivalences, by means of the nerve functor N : Cat → SS from the category Cat of small categories, with respective homotopy categories associated to Cat are established. Consequently, an equivariant simplicial...

This paper defines homology in homotopy type theory, in the process stable homotopy groups are also defined. Previous research in synthetic homotopy theory is relied on, in particular the definition of cohomology. This work lays the foundation for a computer checked construction of homology.

Consider the Fukaya category associated to a Lefschetz fibration. It turns out that the Floer cohomology of the monodromy around∞ gives rise to natural transformations from the Serre functor to the identity functor, in that category. We pay particular attention to the implications of that idea for Lefschetz pencils.

Let S = k[x1, . . . , xn] be a polynomial ring over a field k and I a monomial ideal of S. It is well known that the Poincaré series of k over S/I is rational. We describe the coefficients of the denominator of the series and study the multigraded homotopy Lie algebra of S/I.

In this paper, we apply Homotopy Analysis Transform Method (HATM) for solving various nonlinear equations. This method is the combined for of the homotopy analysis method and Laplace transform method. HATM is applied without any discretization or restrictive assumption and avoids roundoff errors which may lead the solution in closed form. The results reveal that the HATM is very effective, conv...