Why does the converse of the Isomorphism Theorem in first-order logic not hold?
9074
Example of non-isomorphic structures which are elementarily equivalent
33702
Is this an isomorphism possible?
41363
when is f@g not the same as f[g]?
93017
Isomorphism between $\Bbb R$ and $\Bbb R(X)$?
75007
How can I prove this relation between the elementary set theory and the elementary logic?
70872
Isomorphism of quotient modules implies isomorphism of submodules?
20556
Isomorphism between two models of Hilbert's Axioms with different notions of congruence
117131
Canonical Isomorphism Between $\mathbf{V}$ and $(\mathbf{V}^*)^*$
6385
Minimal counterexamples of the isomorphism problem for integral group rings
55778
Group theoretic meaning of natural isomorphisms between certain functors
86248
Is $\exists x(x=a)$ a valid formula in first order logic with equality?
5293
Show that the logic $ \ \forall x \exists y \ P(x,y) \ $ is not logically equivalent to $ \ \exists x \forall y \ P(x,y) \ $
154318
Can a field be isomorphic to its subfield?
82739
Why is $\alpha \rightarrow \forall x(\alpha)$ not generally correct in first-order logic?
90071
Why don't we have an isomorphism between $R[x]$ and $ R[[x]]$?
140962
Counterexamples for $G \times H$ isomorphic to $G$ implies $H$ trivial.
114550
Well-ordering theorem and second-order logic