The reality of a thing is its state of existed, exists, or will exist in the world, independent on the understanding of human beings, which implies that the reality holds on by human beings is local or gradual, and mainly the Mathematical reality, not the reality of a thing. Is our mathematical theory can already be used for understanding the reality of all things in the world? The answer is not because one can not holds on the reality in many fields. For examples, the elementary particle system or ecological system, in which there are no a classical mathematical subfield applicable, i.e., a huge challenge now is appearing in front of modern mathematicians: To establish new mathematics adapting the holds on the reality of things. I research mathematics with reality beginning from 2003 and then published papers on fields, such as those of complex system and network, interaction system, contradictory system, biological populations, non-solvable differential equations, and elementary established an entirely new envelope theory for this objective by flows, i.e., mathematical combinatorics, or mathematics over graphs, which is an appropriated way for understanding the reality of a thing because it is complex, even contradictory. This book collects my mainly papers on mathematics with reality of a thing from 2007 – 2017 and most of them are the plenary or invited reports in international conferences.

招标采购是一种微观经济行为。但为什么要招标，又应当怎样进行招标，国内许多人对此一直存有不解或疑惑，导致实践中一些的招标投标活动走形式、走过场，偏离了招标采购宗旨。本书以采购经济理论为基础，以还原招标采购初心、剖析招标投标规则、阐释采购经济理论为动机，以故事或案例分析为引导，由浅入深、从宏观到微观，系统阐释招标采购的理念和经济学规则，总结招标采购理论。同时，以人的社会属性和修养为基础，剖析串通投标、弄虚作假、挂靠、恶意低价中标等骗取中标行为的深层次原因和对策，构建规范有序的招标投标市场。本书适合于从事招标采购与合同管理理论研究、招标投标市场建设和管理，以及招标采购从业机构和人员理解招标投标机制的参考。同时，本书也可作为高等学校招标采购与合同管理相关专业的本科生或者研究生教学或参考用书。

Unlike particles in the classical dynamics, the dynamical behavior of a complex network maybe not synchronized but fragmented, even a heterogenous moving in the eyes of human beings, which finally results in characterizing a complex network by random method or probability with statistics sometimes. However, such a dynamics on complex network is quite different from dynamics on particles because all mathematics are established on compatible systems but none on a heterogenous one. Naturally, a heterogenous system produces a contradictory system in general which was abandoned in classical mathematics but exists everywhere, i.e., it is inevitable if we would like to understand the reality of things in the world. Thus, we should establish such a mathematics on those of elements that contradictions appear together peacefully but without loss of the individual characters. For this objective, the network or in general, the continuity flow is the best candidate of the element, i.e., mathematical elements over a topological graph G in space. The main purpose of this paper is to establish such a mathematical theory on networks, including algebraic operations, differential and integral operations on networks, G-isomorphic operators, i.e., network mappings remains the unchanged underlying graph G with a generalization of the fundamental theorem of calculus, algebraic or differential equations with flow solutions and also, the dynamical equations of network with applications to other sciences by e-indexes on network. All of these results show the importance, i.e., quantitatively characterizing the reality of things by mathematical combinatorics.

Actually, one establishes mathematicalmodel for understanding a natural thing or matter $T$ by its mathematical property $\widehat{T}$ characterized by model, called mathematical reality. {\it Could we always conclude the equality $\widehat{T}=T$ in nature}? The answer is disappointing by Godel's incomplete theorem which claims that any formal mathematical axiom system is incomplete because it always has one proposition that can neither be proved, nor disproved in this system. Thus, we can not determine $\widehat{T}=T$ or $\not=T$ sometimes by the boundary of mathematics. Generally, a natural thing or matter is complex, even hybrid with other things. Unlike purely thinking, physics and life science determine natural things by subdividing them into irreducible but detectable units such as those of quarks, gluons or cells, i.e., the composition theory of $T$ in the microcosmic level, which concludes the reality of $T$ is the whole behavior of a complex network induced by local units. However, all mathematical elements can only determines the character of $T$ locally and usually brings about a contradictory system in mathematics. {\it Could we establish a mathematics on complex networks avoiding Godel's incomplete theorem for science, i.e., mathematical combinatorics}? The answer is positive motivated by the traditional Chinese medicine, in which a living person is completely reflected by $12$ meridians with balance of Yin ($Y^-$) and Yang ($Y^+$) on his body, which alludes that there is a new kind of mathematical elements, called {\it harmonic flows} $\overrightarrow{G}^{L^2}$ with edge labeled by $L^2:(v,u)\in E\left(\overrightarrow{G}\right)\rightarrow L(v,u)-iL(v,u))$, where $i^2=-1$, $L(v,u)\in\mathscr{B}$ and $2$ end-operators $A_{vu}^+, A_{vu}^-$ on Banach space $\mathscr{B}$ holding with the continuity equation on vertices $v\in V\left(\overrightarrow{G}\right)$ with dynamic behavior characterized by Euler-Lagrange equations.